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MIGROCOPY RESOLUTION TEST CH~RT

NATIONAL BURICAU OF STANDARDS-196i-A

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MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS-J963-A

Technical Bulletin No 842 AprilY943

Contribution to the Morphology and Anatshyomy of Guayule CParthenium argentatum)l By Eaxsl AIlTSCIlWAOfR ~flIiol plallt allatomist Rllbbel PZlLIlt Il1vestigatio118

BIIIeuu of Plallt IIIits(I1I L1YIicllltllral Reseulch l1dlllillistrafion

CONTENTS

~r __ ~ __

IugeIntroduction bullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bullbullbullbull I Anatomy of mature stem-Continued--rnterinls nnd nHthOlls _______ ~ __ 2 lhloem-Continucd Gross morpholo~ybull _ 3 Inllctio phIOlm 24 MOrholOgy of flowtrs nnd std _ 4 P~ridcrm 24 Seed lng structurt 7 Anatomy of root 26

a~nernllllorphoJogy~ __ ~ bullbull ~ 26 ~_~ __ 7 Xylem Anatomy S lhloem 26

Hoot S Actio secondary phloem bull___ rT

D~tlnito stem bullbullbull IS

Hypocotyl bullbullbull 1() Old phloem __ rT EpltOtyL 14 Structuro of the petluncle ___ 28

Structure of the leuL ______ _____ ___ 28 Anatomy of maturo stem 19 Cotyledon__ ______ bull____bullbullbullbull__ bullbull_bull_ 28

Gcncralstrueturc HI lruc leaL ___ 28 Xylem 21 Origin and storago ofrubber_____ 31 Pbloe01 __ 21 Anatomical structure in relation to rubber conmiddot

Active phloem 21 tentnnd type____ 32 SetOndnry resin cnnis 23 Literature cited ______bull____ 33

~ INTRODUCTION ~ The researches of Ross (5)3 and Lloyd (4) have shown that rubber ~storage in guayule is a function of the living parenchyma cell of root ~nd stem In plants of harvest size these cells are limited largely to

- sl11e tlscular rays and the cells around the secondary resin canals athereas in young material the primary cortex and pith are of greater nnportance tlAlthough rubbetmiddot secretion is a physiological function of the cell tliat may differ in intensity in difrerent plants and under different

~uctule that is a plant with a greater storage capacity one that h~ a broader secondary cortex and -ider und more numerous vasshyc~r rays should outyicld a plant in which the anatomical picture reveftls 11 preponderance of mechanical tissue

Three decades of breeding work at Salina Calif have produced varieties that outperform indigenous plants both in total yield and in

etrvironmental conditions performance is evidently bound up with

1 Suhmitt(l for publication SltPtemb(r 2 1042 Credit is due to ~Irs Eug(nia Artschwnger for Plcparutlon of the drawings IlDd to

R A Lllubell-ayer Cornell University for embedding certnin gunyulc IUllterial in celloidin nnd pnpnrillg slldes of somt of it

gt Italic nUlllurs in parcnthc~e~ rdor to Literuturc Cited p 33 middotIlS670--l3--1 1

2 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTURE

percentage of rubber Individuals of these hiOh-yielding strains if theiL anawmy wert known should have a broaer secondary cortex and a minimum amount of sclerenchymatous tissue the vascular rays of the xylem would be broad and nUI1HIOUS they would grow rapidly in the spring producing a favorable balance of phloem tissue and ynthesize a maximum amount of rubber within the shortest time intelal between seasons of growth One might further project that such plants would not be too choosy in regard to soil requirements and could be fitted plOfitably into existing systems of crop rotation

Unfortnnately asille from conspicuous grosser morphologicn1 difshyfetences little is known about the distilHuishing anatomical ch1I(lcshytelisticsof high- and low-yielding varietIes still less about the effect of environmellt on strudure and nothing at all about the cause of rerersion from high rubber content to low when put in a different rnvilonment

Rapid growth and inirnsity of rubber storage are mutually exshyrlusiye unless a suitable rest period is allowed for rubber synthesis to he effectin Rapid growth although producing a larger totnl increshyment of both xylem and phloem faYols xylem deyelopment unless gLOwth is SUsp(ll(led by the yithholdiug of irrigation water after a JI1aximum amollnt of phloem has been fo)med I)lants differ not only bull in their ability to PlOclUCC a lelatie growth increment of xylem and phlol but also in regard to difie)entiation priority between the two lissltc~ In muny plnnts the cambium difftrentiates a ccrtain amount of phloem first when growth is resumed in the spring and guayu]e appears to b( OIlC of them nlthough our knowledge concerning this point is mostly empirical

Ross (J) anLl Lloyc1 (4) through their studies haye given us a geneml insight into the anntomy of the plant the ontogeny of the tissues and the plnce and time for rubber synthesis but they tell us nIT little about the detailed structure of the secondary xylem nnc1 phloem so important in the c1cn~lopment of the plant frolTt the standshypoint of performance

This bulletin aims to consider critically and btiefly the plant in its ntirety laying emphasis on tllctural features that have been ))reshyiollsly l1egle(ted or omittNl and that in the authors opinion have a direct bearing on breeding to setTe the present need

MATERIALS AND METHODS

Most of tIl( material fOl study caml from the United Stnhs Cotton liilld Station at Stnte College N Mlx having been imporl((l a lIecshync1e ago f)oll1 yarious parts of thl Rig Rend area of Texas with sonw from Salinas Calif The usual hchniqtll of fixing and staining WIIS

employee but often had to he abnndoned in favor 01 hand sections of fresh material Old sl-111 and root mahrial treated with hrclroshyAUOlic acid and elllbec1dd in celloidin prond us(ess for the stlldy of the sNonduly phloPI11 but untTeatlll dissP(ted se(onlt1aly phloelll elllbedded in Ianl parilnn and stained with iron llllm haelllntoxVlin ~howed finc difilIlntiation (en though 011 a((ollnt of tIll 1a11 Hmount of sclelenChyma tIl( pelions (1( -omewhat ragNl ~ra(ershyatioll of the xylelll iol a study of its (omponpnts 1 cllIied out in a mixture of 10 percent chromic aeid aud 10 percent nitric acid

bull

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IIHIadlli nI1lllllil1 ~lld1l Til Ira lH flll tltp ilaillill~ or lI1hlwl Lh Illlkill~ thl 1Itilllh raill (Ililk alld Ia-hill~ tli()I()II~lih ill nltooshyIt artlI -tnillili it t PlJ~ihL In lllIlOlI fluill thl lI(i()il all IllbshyIHI tltat Illi~tl l1liLilIIIlIImiddot tl( 111111 drliiltl Iitll I Ill kllilt illto ldjllllll lllk ~lllh a 1[(1)IIlli(111 l(JllllllI--laillld witl (Illollli()ditil I III -hllI11 ill ldditillil t) 11111[1 IIII 111(111(111 or (lI(1 (0 hlt a h alIt lUI

11 1II()tll~lnpll 1[11 takell (III lltlllI ~[ Ila(I Iilll Hlilahll Ltlll lilllI Tin dl1 ill a11 II[(HI III-Id Ull 1IIIItllllliluglllh-

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1 n (11 1IIIlldI llr tltl (rilll 1I1lillltltlI 1lllId1 (llljltl-I1I i-I 1(1ilI-III I1Jl IwhillU -11Jllh I(Ilillill~ III tIl)

- 1 LI I -totlll 1111 11-- Ilt1l1 11(1 I Ii II ILl 11l( --111 (Ii ~l lii- th1 11 111111 tIIJ 11-111 -hllI-

(11 -1- I 1 tflltl( lilll 1111111 )Itl- 1 iliJ till -lib-III til 1 -1-shy

11111 I _d l IIt- lit11 1111101- 11gtitlllltfl rt[ I1111 di[llltIshy11 Ilh--Iiigt- Idlill 11lt(11- 11111 1111 1IIIir (illlItt1 [hI 11

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4 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTuRE

The young stem is silvery gray and densely clothed with hairs As the epidermis is shed and cork und lenticels develop the surface becomes gray later brownish it is generally fissured with shallow sometimes deep corky crack and parts may be covered with deposits of resin oozing out from the peripheral canals

FIGURE 2-Surfnce root system of young plant

The leaves are inserted on the stem in a spiral with t divergence of 25 However opposite and even whorled arrangements may be found on the same stem The leaves are lanceolnte usually crenate)y toothed Oi cut-lobed below the middle and densely covered with asymmetrical T-shnped hairs the leaf form is very variable During the winter months only the terminal leaf clusters are retained these leaves are smaller than the summer leaves lanceolate and rarely lobed

The inflorescence (pI 1 A) is a compound one-sided cyme with lateral axes exceeding the main axis in length

MORPHOLOGY OF FLOWERS AND SEED

The morphology of the flowers of guaynle and the related species Palfhelliullb hysteloph01U8 L has been treated in great detail by Kokieva (j) and a slJnilar detailed treatise by Dinnonl and coworkers (3) furnishes tl comparative cytoembryological analysis of P argenshytal7blll Gray and P illcanum Gray

The flowers of ~uayule are bome ill close heads on a common reshyceptacle The hends arc rarely solitnry commonly a number of them are grouped close together (pI 1 A) and since they arc not initiated simultancously flowering extends over a long period Each flower head consists of 5 involucral leaves (fig ~ B) that

oerlap slightly at the base AboYe the involucral leavcs and altershynating with them ttre 5 bracts containing 1n their axils the 5 ligulate Oi ray flowers (fig 3 Lt E) Adnate to each ligulate flower are 2 disk flowers enclosed in saclike hracts (fig 1 F and fig 4 A) The- renmining sUtface of the elik i filled with disk flowers and their bracts (fig 3 A) The brads of the ligulat flower are almost round and thcir surface is dcnsely (oerec1 with hairgt 1hogte of the disk flowers are membranaceous scales with infolded margins (fig 3 D) also densely pubescent and each with ltl solitary vascular

c

5 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGllu t-A ~lIrfall Yil M 1I0(r hlld lhoill~ ri Iigulltl and 2-1 llik t111wlmiddotr~ ll (Ill I yip or Huw1 htad (or lollI or (1lola T (11111 latpral aWII illl imllll(mi llaf () hlIe (If ray nllPr lcli Illmiddott1kll (IDnlalglt rpm ilw of lIIatlll hCIIl willi inyolueral hllIct 1llIIOpd III show Olillill of lchen(s tpri 1( Bowcn II tlll(hpti til I helll ray (olllllll~ and 1)1111118 J) Disk HOIl with its (11(10111 hract T~ lIlalgld ilw of mI t10l1 III its iJraet without it disk tllt)w(r P Ua) Hower with iis ~ Illllllltc disk t1oWC1S

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

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8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

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PLATE 5

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13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

2 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTURE

percentage of rubber Individuals of these hiOh-yielding strains if theiL anawmy wert known should have a broaer secondary cortex and a minimum amount of sclerenchymatous tissue the vascular rays of the xylem would be broad and nUI1HIOUS they would grow rapidly in the spring producing a favorable balance of phloem tissue and ynthesize a maximum amount of rubber within the shortest time intelal between seasons of growth One might further project that such plants would not be too choosy in regard to soil requirements and could be fitted plOfitably into existing systems of crop rotation

Unfortnnately asille from conspicuous grosser morphologicn1 difshyfetences little is known about the distilHuishing anatomical ch1I(lcshytelisticsof high- and low-yielding varietIes still less about the effect of environmellt on strudure and nothing at all about the cause of rerersion from high rubber content to low when put in a different rnvilonment

Rapid growth and inirnsity of rubber storage are mutually exshyrlusiye unless a suitable rest period is allowed for rubber synthesis to he effectin Rapid growth although producing a larger totnl increshyment of both xylem and phloem faYols xylem deyelopment unless gLOwth is SUsp(ll(led by the yithholdiug of irrigation water after a JI1aximum amollnt of phloem has been fo)med I)lants differ not only bull in their ability to PlOclUCC a lelatie growth increment of xylem and phlol but also in regard to difie)entiation priority between the two lissltc~ In muny plnnts the cambium difftrentiates a ccrtain amount of phloem first when growth is resumed in the spring and guayu]e appears to b( OIlC of them nlthough our knowledge concerning this point is mostly empirical

Ross (J) anLl Lloyc1 (4) through their studies haye given us a geneml insight into the anntomy of the plant the ontogeny of the tissues and the plnce and time for rubber synthesis but they tell us nIT little about the detailed structure of the secondary xylem nnc1 phloem so important in the c1cn~lopment of the plant frolTt the standshypoint of performance

This bulletin aims to consider critically and btiefly the plant in its ntirety laying emphasis on tllctural features that have been ))reshyiollsly l1egle(ted or omittNl and that in the authors opinion have a direct bearing on breeding to setTe the present need

MATERIALS AND METHODS

Most of tIl( material fOl study caml from the United Stnhs Cotton liilld Station at Stnte College N Mlx having been imporl((l a lIecshync1e ago f)oll1 yarious parts of thl Rig Rend area of Texas with sonw from Salinas Calif The usual hchniqtll of fixing and staining WIIS

employee but often had to he abnndoned in favor 01 hand sections of fresh material Old sl-111 and root mahrial treated with hrclroshyAUOlic acid and elllbec1dd in celloidin prond us(ess for the stlldy of the sNonduly phloPI11 but untTeatlll dissP(ted se(onlt1aly phloelll elllbedded in Ianl parilnn and stained with iron llllm haelllntoxVlin ~howed finc difilIlntiation (en though 011 a((ollnt of tIll 1a11 Hmount of sclelenChyma tIl( pelions (1( -omewhat ragNl ~ra(ershyatioll of the xylelll iol a study of its (omponpnts 1 cllIied out in a mixture of 10 percent chromic aeid aud 10 percent nitric acid

bull

)

IIHIadlli nI1lllllil1 ~lld1l Til Ira lH flll tltp ilaillill~ or lI1hlwl Lh Illlkill~ thl 1Itilllh raill (Ililk alld Ia-hill~ tli()I()II~lih ill nltooshyIt artlI -tnillili it t PlJ~ihL In lllIlOlI fluill thl lI(i()il all IllbshyIHI tltat Illi~tl l1liLilIIIlIImiddot tl( 111111 drliiltl Iitll I Ill kllilt illto ldjllllll lllk ~lllh a 1[(1)IIlli(111 l(JllllllI--laillld witl (Illollli()ditil I III -hllI11 ill ldditillil t) 11111[1 IIII 111(111(111 or (lI(1 (0 hlt a h alIt lUI

11 1II()tll~lnpll 1[11 takell (III lltlllI ~[ Ila(I Iilll Hlilahll Ltlll lilllI Tin dl1 ill a11 II[(HI III-Id Ull 1IIIItllllliluglllh-

CI(l~ It ll lIIOI()eY

1 n (11 1IIIlldI llr tltl (rilll 1I1lillltltlI 1lllId1 (llljltl-I1I i-I 1(1ilI-III I1Jl IwhillU -11Jllh I(Ilillill~ III tIl)

- 1 LI I -totlll 1111 11-- Ilt1l1 11(1 I Ii II ILl 11l( --111 (Ii ~l lii- th1 11 111111 tIIJ 11-111 -hllI-

(11 -1- I 1 tflltl( lilll 1111111 )Itl- 1 iliJ till -lib-III til 1 -1-shy

11111 I _d l IIt- lit11 1111101- 11gtitlllltfl rt[ I1111 di[llltIshy11 Ilh--Iiigt- Idlill 11lt(11- 11111 1111 1IIIir (illlItt1 [hI 11

r I 1gt 1 III Jilill [1 lilt -ttlll) Illlli-lltI ul -[nil ~1(1 ~ t ttl U-

4 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTuRE

The young stem is silvery gray and densely clothed with hairs As the epidermis is shed and cork und lenticels develop the surface becomes gray later brownish it is generally fissured with shallow sometimes deep corky crack and parts may be covered with deposits of resin oozing out from the peripheral canals

FIGURE 2-Surfnce root system of young plant

The leaves are inserted on the stem in a spiral with t divergence of 25 However opposite and even whorled arrangements may be found on the same stem The leaves are lanceolnte usually crenate)y toothed Oi cut-lobed below the middle and densely covered with asymmetrical T-shnped hairs the leaf form is very variable During the winter months only the terminal leaf clusters are retained these leaves are smaller than the summer leaves lanceolate and rarely lobed

The inflorescence (pI 1 A) is a compound one-sided cyme with lateral axes exceeding the main axis in length

MORPHOLOGY OF FLOWERS AND SEED

The morphology of the flowers of guaynle and the related species Palfhelliullb hysteloph01U8 L has been treated in great detail by Kokieva (j) and a slJnilar detailed treatise by Dinnonl and coworkers (3) furnishes tl comparative cytoembryological analysis of P argenshytal7blll Gray and P illcanum Gray

The flowers of ~uayule are bome ill close heads on a common reshyceptacle The hends arc rarely solitnry commonly a number of them are grouped close together (pI 1 A) and since they arc not initiated simultancously flowering extends over a long period Each flower head consists of 5 involucral leaves (fig ~ B) that

oerlap slightly at the base AboYe the involucral leavcs and altershynating with them ttre 5 bracts containing 1n their axils the 5 ligulate Oi ray flowers (fig 3 Lt E) Adnate to each ligulate flower are 2 disk flowers enclosed in saclike hracts (fig 1 F and fig 4 A) The- renmining sUtface of the elik i filled with disk flowers and their bracts (fig 3 A) The brads of the ligulat flower are almost round and thcir surface is dcnsely (oerec1 with hairgt 1hogte of the disk flowers are membranaceous scales with infolded margins (fig 3 D) also densely pubescent and each with ltl solitary vascular

c

5 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGllu t-A ~lIrfall Yil M 1I0(r hlld lhoill~ ri Iigulltl and 2-1 llik t111wlmiddotr~ ll (Ill I yip or Huw1 htad (or lollI or (1lola T (11111 latpral aWII illl imllll(mi llaf () hlIe (If ray nllPr lcli Illmiddott1kll (IDnlalglt rpm ilw of lIIatlll hCIIl willi inyolueral hllIct 1llIIOpd III show Olillill of lchen(s tpri 1( Bowcn II tlll(hpti til I helll ray (olllllll~ and 1)1111118 J) Disk HOIl with its (11(10111 hract T~ lIlalgld ilw of mI t10l1 III its iJraet without it disk tllt)w(r P Ua) Hower with iis ~ Illllllltc disk t1oWC1S

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

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~ ~ g ~ Fmiddot=~

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llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

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bull

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MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

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21

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MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

)

IIHIadlli nI1lllllil1 ~lld1l Til Ira lH flll tltp ilaillill~ or lI1hlwl Lh Illlkill~ thl 1Itilllh raill (Ililk alld Ia-hill~ tli()I()II~lih ill nltooshyIt artlI -tnillili it t PlJ~ihL In lllIlOlI fluill thl lI(i()il all IllbshyIHI tltat Illi~tl l1liLilIIIlIImiddot tl( 111111 drliiltl Iitll I Ill kllilt illto ldjllllll lllk ~lllh a 1[(1)IIlli(111 l(JllllllI--laillld witl (Illollli()ditil I III -hllI11 ill ldditillil t) 11111[1 IIII 111(111(111 or (lI(1 (0 hlt a h alIt lUI

11 1II()tll~lnpll 1[11 takell (III lltlllI ~[ Ila(I Iilll Hlilahll Ltlll lilllI Tin dl1 ill a11 II[(HI III-Id Ull 1IIIItllllliluglllh-

CI(l~ It ll lIIOI()eY

1 n (11 1IIIlldI llr tltl (rilll 1I1lillltltlI 1lllId1 (llljltl-I1I i-I 1(1ilI-III I1Jl IwhillU -11Jllh I(Ilillill~ III tIl)

- 1 LI I -totlll 1111 11-- Ilt1l1 11(1 I Ii II ILl 11l( --111 (Ii ~l lii- th1 11 111111 tIIJ 11-111 -hllI-

(11 -1- I 1 tflltl( lilll 1111111 )Itl- 1 iliJ till -lib-III til 1 -1-shy

11111 I _d l IIt- lit11 1111101- 11gtitlllltfl rt[ I1111 di[llltIshy11 Ilh--Iiigt- Idlill 11lt(11- 11111 1111 1IIIir (illlItt1 [hI 11

r I 1gt 1 III Jilill [1 lilt -ttlll) Illlli-lltI ul -[nil ~1(1 ~ t ttl U-

4 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTuRE

The young stem is silvery gray and densely clothed with hairs As the epidermis is shed and cork und lenticels develop the surface becomes gray later brownish it is generally fissured with shallow sometimes deep corky crack and parts may be covered with deposits of resin oozing out from the peripheral canals

FIGURE 2-Surfnce root system of young plant

The leaves are inserted on the stem in a spiral with t divergence of 25 However opposite and even whorled arrangements may be found on the same stem The leaves are lanceolnte usually crenate)y toothed Oi cut-lobed below the middle and densely covered with asymmetrical T-shnped hairs the leaf form is very variable During the winter months only the terminal leaf clusters are retained these leaves are smaller than the summer leaves lanceolate and rarely lobed

The inflorescence (pI 1 A) is a compound one-sided cyme with lateral axes exceeding the main axis in length

MORPHOLOGY OF FLOWERS AND SEED

The morphology of the flowers of guaynle and the related species Palfhelliullb hysteloph01U8 L has been treated in great detail by Kokieva (j) and a slJnilar detailed treatise by Dinnonl and coworkers (3) furnishes tl comparative cytoembryological analysis of P argenshytal7blll Gray and P illcanum Gray

The flowers of ~uayule are bome ill close heads on a common reshyceptacle The hends arc rarely solitnry commonly a number of them are grouped close together (pI 1 A) and since they arc not initiated simultancously flowering extends over a long period Each flower head consists of 5 involucral leaves (fig ~ B) that

oerlap slightly at the base AboYe the involucral leavcs and altershynating with them ttre 5 bracts containing 1n their axils the 5 ligulate Oi ray flowers (fig 3 Lt E) Adnate to each ligulate flower are 2 disk flowers enclosed in saclike hracts (fig 1 F and fig 4 A) The- renmining sUtface of the elik i filled with disk flowers and their bracts (fig 3 A) The brads of the ligulat flower are almost round and thcir surface is dcnsely (oerec1 with hairgt 1hogte of the disk flowers are membranaceous scales with infolded margins (fig 3 D) also densely pubescent and each with ltl solitary vascular

c

5 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGllu t-A ~lIrfall Yil M 1I0(r hlld lhoill~ ri Iigulltl and 2-1 llik t111wlmiddotr~ ll (Ill I yip or Huw1 htad (or lollI or (1lola T (11111 latpral aWII illl imllll(mi llaf () hlIe (If ray nllPr lcli Illmiddott1kll (IDnlalglt rpm ilw of lIIatlll hCIIl willi inyolueral hllIct 1llIIOpd III show Olillill of lchen(s tpri 1( Bowcn II tlll(hpti til I helll ray (olllllll~ and 1)1111118 J) Disk HOIl with its (11(10111 hract T~ lIlalgld ilw of mI t10l1 III its iJraet without it disk tllt)w(r P Ua) Hower with iis ~ Illllllltc disk t1oWC1S

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

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PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

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PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

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redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

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llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

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lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

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A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

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MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

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20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

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A

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B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

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21

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MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

4 TECHNICAL BULLETIN 842 U S DEPT OF AGRICULTuRE

The young stem is silvery gray and densely clothed with hairs As the epidermis is shed and cork und lenticels develop the surface becomes gray later brownish it is generally fissured with shallow sometimes deep corky crack and parts may be covered with deposits of resin oozing out from the peripheral canals

FIGURE 2-Surfnce root system of young plant

The leaves are inserted on the stem in a spiral with t divergence of 25 However opposite and even whorled arrangements may be found on the same stem The leaves are lanceolnte usually crenate)y toothed Oi cut-lobed below the middle and densely covered with asymmetrical T-shnped hairs the leaf form is very variable During the winter months only the terminal leaf clusters are retained these leaves are smaller than the summer leaves lanceolate and rarely lobed

The inflorescence (pI 1 A) is a compound one-sided cyme with lateral axes exceeding the main axis in length

MORPHOLOGY OF FLOWERS AND SEED

The morphology of the flowers of guaynle and the related species Palfhelliullb hysteloph01U8 L has been treated in great detail by Kokieva (j) and a slJnilar detailed treatise by Dinnonl and coworkers (3) furnishes tl comparative cytoembryological analysis of P argenshytal7blll Gray and P illcanum Gray

The flowers of ~uayule are bome ill close heads on a common reshyceptacle The hends arc rarely solitnry commonly a number of them are grouped close together (pI 1 A) and since they arc not initiated simultancously flowering extends over a long period Each flower head consists of 5 involucral leaves (fig ~ B) that

oerlap slightly at the base AboYe the involucral leavcs and altershynating with them ttre 5 bracts containing 1n their axils the 5 ligulate Oi ray flowers (fig 3 Lt E) Adnate to each ligulate flower are 2 disk flowers enclosed in saclike hracts (fig 1 F and fig 4 A) The- renmining sUtface of the elik i filled with disk flowers and their bracts (fig 3 A) The brads of the ligulat flower are almost round and thcir surface is dcnsely (oerec1 with hairgt 1hogte of the disk flowers are membranaceous scales with infolded margins (fig 3 D) also densely pubescent and each with ltl solitary vascular

c

5 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGllu t-A ~lIrfall Yil M 1I0(r hlld lhoill~ ri Iigulltl and 2-1 llik t111wlmiddotr~ ll (Ill I yip or Huw1 htad (or lollI or (1lola T (11111 latpral aWII illl imllll(mi llaf () hlIe (If ray nllPr lcli Illmiddott1kll (IDnlalglt rpm ilw of lIIatlll hCIIl willi inyolueral hllIct 1llIIOpd III show Olillill of lchen(s tpri 1( Bowcn II tlll(hpti til I helll ray (olllllll~ and 1)1111118 J) Disk HOIl with its (11(10111 hract T~ lIlalgld ilw of mI t10l1 III its iJraet without it disk tllt)w(r P Ua) Hower with iis ~ Illllllltc disk t1oWC1S

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

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8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

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PLATE 5

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-1

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13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

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PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

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redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

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llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

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lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

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A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

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MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

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20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

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B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

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MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

5 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGllu t-A ~lIrfall Yil M 1I0(r hlld lhoill~ ri Iigulltl and 2-1 llik t111wlmiddotr~ ll (Ill I yip or Huw1 htad (or lollI or (1lola T (11111 latpral aWII illl imllll(mi llaf () hlIe (If ray nllPr lcli Illmiddott1kll (IDnlalglt rpm ilw of lIIatlll hCIIl willi inyolueral hllIct 1llIIOpd III show Olillill of lchen(s tpri 1( Bowcn II tlll(hpti til I helll ray (olllllll~ and 1)1111118 J) Disk HOIl with its (11(10111 hract T~ lIlalgld ilw of mI t10l1 III its iJraet without it disk tllt)w(r P Ua) Hower with iis ~ Illllllltc disk t1oWC1S

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

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i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

6 TECHNICAL BULLETIN 8lt12 U S DEPT OF AGRICULTURE

middotmiddotmiddotmiddotmiddotQJl

FHHIII -1-1 Diagrnlllllla tic drawillg of trlSS scliioll through basp of ray Ilmypr alld its mljaett lIis Howprs to show 1llIatioll X [2 B DItailcd drawing nl mature oymT wnii X 750 cp EpidtlllIis CIC cso(lclInis j 1) 1 lligmcllllli lay j 11 lIICiOoca Ill j en clldoca ll

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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a ~

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G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

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i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

Technicnl Bulletin 8middot12 U S Department of Agriculture PLATE 1

( f

I I

_I 1llanch of intinrcCpnCP with nOWlr in variou stages of dlYllovment B-D gerlllinating lLLl E-]i yuuug seedlings G ulder seedling

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

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g tshy

shyif

E ~ -c C

rg

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sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

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i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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[ tgt c ~ 0gt

-bull f=

f ~

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

Technicl Bulletin 842 U S Department ol Agriculture PLATE 2

lt1 Young eclllings showing root hYilocotyl Hml olle l)air of foliage leaves B Seedling axis at jUlIction of hYllocotyl null root just below bulge the first lateral root makes its appearance

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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a ~

laquo

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shyif

E ~ -c C

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sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

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i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-bull f=

f ~

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

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21

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MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

7 MORPHOLOGY AND ANATOMY OF GUAYULE

bull bundle The blacts of the 10 disk flowers tl1at arc adnnte to the ray flowers (fig- 3 F) arc saclike and have 3 vascular bundles each

The corolla of the ray flower is sharply cleft in front (fig 3 F) I entire or slightly cleft ill the rear The corolla of the disk flower is five-lobed and its five vascular bundles terminate between the teeth of the corolla tube

The pistil of the ray flower is formed by two carpels grown toshygtther in titlt UPIWl llgion to fOlm a short style that t(1111inates in two stigmatic lolws of equal height (fig 3 E F) The style is tlllVshy(lsed by two bundles its outside is covere(l by a thick velvety publscpncp The olIle is tlnatropollS ovnte and flattened tangentially

The oaly Yall (fig 4 B) has tl singk-laYNecl outer ltpidermis that abuts on a IOW of tall palisade cllIs A layer of s111all thick-walled tH)(IS composlS the Illtmetlp Bltweell the lI1eSOCalp and palisade ((]]s is a nlal1-tllh~d pigll1lnted layer characterized by radial papillae and yellow eontpnt that JatN tUlnH brown The endocarp is made lip of lomil 11IPgulal parPllehYl1la eells There are four vascular bundles tlaYersing the ovary wall those vassing through the keels and those running through the eenter of the anterior and posterior walls

The necialY forms a Hholt tubp that c1asps the stylp almost adshyhering to the outer wall The pappus (fig 3 E) consists of a short nnttnl alHl tYo lateral nynH ellnsely pubescent and with a solitary Yaculnr bundle

The disk flowltrs have fin~ stamens grown togpther to form a short tnbe that is atlnatp to tIl( corollt for about half the length Each filament has OIl( yasclila l bundle The pistil of the disk flower lacks an oyal) Ctyity tis at first sltOltPI than the stamens but elongates 11(11 the flow(r matlins pushing up the p01l(11 in the pr()eess

WIl(n the fruit is ripe the floYelmiddotheads disintegrate the ray flowers that bea r tilt scd rp 111 a i II attaeilP(1 to their adjactnt disk flowers aud their il1olllcral bllcis and fall away as a whole The remainshying disk flowers alHo drop oil leaing behind the five involucral brads attHIll(1 to tlw rlceptaclp

lh( aetual fruit is lin aehplle with a ellY indehiscent pericnrp shri(~IIld (orolla and thrpe HllOlt awns The a(hen( itself is obovate and ta ng(ntia Ily Ila ttelled (la [k gray Ot almost black anll covered with short hairs

SEEDLING STRUCTURE

GENERAL MORPHOLOGY

Gllnyultgt se(d unless iJ)leially tllat(d is slow and difficult to glt11111shynate The root pwhlH out of till seed cont (pI 1 B 0 D) about (i daYH after planting and the eotyledons appear above ground about R clays la tpr

Thp young He(1lin has a long taproot a short hypocotyI and oyal nt olhillllal (middototyledons (p1 2 A) The base of the hypocotyl is inclienl(d by an abluptincnaHl in diametN (pI 2 B) and the uPPPlaIlCl of tIll first latera I rootlet below the bulge

middotH1S(j7~middot-43-

bull

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

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PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

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PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

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redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

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llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

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A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

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0

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bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

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20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

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A

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B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

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shy

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bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

8 lECFL~ICAL BlLLEllN 842 L S DEPT OF AGRICULTURE

AN-TO~lY bullHOOT

Ill( taploot of the yonnp se((1ling has a (entlll (orc of vllsculur tissue (fig 5 A) 1im itlCl 011 the outside by an endodermis allel a cortex

The pedphern 1 cells of the cortex are covered by a root epidermis a single laycI of small thin-walled cells many of them elongated into root hairs (the latter are not shown in chawing) The cortex is five- to six-layered its cells tre large and possess prominent intershycellular spaces The stele consists of two protoxylem points exshytending centlifngaUy to the pericycle ditfering in that respect from lateIlll rootlets that uecomlUonLy triarch (fig 5B) Between the two l)lotoxylclll points two groups of primary phloem are located and between xylem and phloem is a mass of undiirerentiated parenchyshymatons tissllc that eyentually matures into metaxylem (fig 6) The transformation of this tissue into metaxylem procectls in all directions except for a single layer centrad to the phloem groups which func- bull tions as a eambium itll the delh-ed cells maturing as secondary xylem Otmiddot phlo(m From these points of initial cambium activity there is It progressive development with the zone of cambium extendshying laterally until it reaches the points where the protoxylem cells abut on the pericyclc

As the rootlet enlarges the epidermis breaks down and its cells become lignified The cells of the cortex enlarge and radial divisions become increasingly noticeable among them The endodermis Hlso compensates for stelaI enlargement first throngh increase in size whereby the radial walls extend from the Caslarian strips outward and later by cell increase throngh anticlinal diVIsions

In the l(gion opposite the two primary phloem groups the cudoshydermis becollHS two-layered but no laspalian stlips develop in the upper cells Thl deelopment of this localized double endodc1ll1is is the first step in the fotlllation of the resin canals

The ontogtny of these canals follows a pattern common to the Compositae the cells of the llouble endodellnis divide antiClinally bull laquoiying rise to groups of four cens The -ails at the point h~re the four cells meet pull away all mtelcellulal space forllls lllch gradnally (1l1arts to form the resin canal (pI 3 1) Sometimes the anticlirllil tlimiddotjiltH1R in the double endodelmis extend onIv through th~ outel laycr of cells in which case the cn nal is boundtllby on Ii thlee (dIs 8uhsequclIt periclinal c1iyisiol1s cut otr two tjplS of cells (pI 3 B) the inlier onc knOl as the secreting layer or epithelium

In somewhat older rootlets two small glcmps of fiber may be seen centrad to the cndndellnis and opposite the resin canals (pI 3 B) They usually sllllound and (rush tht plotophloem in their developshyment Although these groups of fibers often adjoin the enclodernlls they also may be locnted several layers inward (fig 7) Theit origin is pericyclic althongh Lloyd does not believe that the pericycle is inyoIycd in their formation

bull

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

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sect If

a ~ ggt

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G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

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redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

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llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

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shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

MOHPHOLOGY AND ANArOMY OF GUAYULE

FIOUltE 5-_ (ross flleti(ln o( ttpr(lOt of ~oung sPldling with (linrrh prQshytoxylllllllah X 250 (p Epi(ltmllis 1 corkx Ill endodermis p llerieyele pr Plotoxylcm ph IriuuQ phlO(IU lJ Cross secmiddottion of triareh rootlet X 250

bull

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

10 rECHNICAL BULLETIN 812 U S DEPT OF AGRICULTURE

FIGUR~ G-ero sf(tion of taproot of sCllllin~ fomewhnt older than rellreshylllted ill figure 5 A ~rhe flludlllllentalllarenchymil JIllS differentiated into JlJetaxylelU some secondary xylem tlfO lUIS been lidded X 560

lIYPOCOTYL

The base of the hypocotyl is lootlike with a primary diarch proshytoxylem plate lind laterally placed phloem glmiddotOUpS The cortex is broader thill1 in the root but there is no increase in diameter of the stele (pI 2 B)

Vascular transition takes place in the hypocotyl but the stelar tissue is not completely collnteral and endarch until approximately the lower third of the cotyledonary midrib is reached The trnnsition agrees in general plan with Alctiwn mhnl8 Bernh as described by Siler (6) The chatlge from the exarch condition in the root to the endarch conshydition in the stem begins in the middle or lower part of the l1ypocotyl and the complete tIHlfllth condition for the midrib bundles is attained some distance lip the cotyledons as prcyiously stated

Neal the middle of the hypocotyl new xylem diffcrentiates 1atcllIlly to form two tangentially exarch bundles (pI 4 d) The protoxylelll

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

Technic1 Bulletin 842 U S Deprtment of Agriculture PLATE 3

_I (10 ~LctiOI of ~ol1ng root showing clllllJdclnwl origin of IIsin canals X -lO B Ia)middottial (lOgt-H p(tion of litH) Clot with l)IinUlIY cortical (anal and grollp of pelicyclic liuers nuoy glOUll of crushed IJlimulY phloem X (JJO

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

bull I Bulletin 842 U S epa f A riculture Technlca D rtment 0 g PLATE 4

I

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

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i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

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-bull f=

f ~

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-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

11 MORPHOLOGY AND ANATOMY OF GUAYULE

FIGlm 7-Palmiddottial elmiddotos w(tioll of imiddotaproot 135 mill ill lliametlr showin~ resin elIIih Iud gTOl[l of fihelmiddots X 410 r Hesill canal CII elldolienllis p perishy(yello pll tlulll1 lllimalr phloem f gloUI) of lJrimHlY fibers 1111 IllimlllY IJhlocm ( eumbium ie xylem

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

12 lECHNICAL BULLETIN 342 11 S DEPT OF AGRICULTURE

points shift progressively centrad nn(l become several cell layers reshymoved frolll the endodermis where they eVClltuany form flat V-shaped double bundls The lateral orientation of newly formed xylem eleshyments coincides with the tan~ential stretching of thp two primary l)hloem gLOUpS and their splittlllg to fOIm four phloem regions which come to lie opposite the xylem of the V-shaped bundles These bundles of the middle andmiddotupper hypocotyl anastomose acconling to It definite pattern to form the vascular supply of the cotyledoJls and the true foliage leayes

In very younl seedlings with embryonic cotyledons the origin and course of the vascular supply is easily followed The V-shaped double bundles become the midrib bundlls of the two cotyledons while the InternI traces arise some distanee downward These lateral traces run separately for 11 considelllhle distance ucfore they split to supply two lateral bUJldles to eaeh eo(yledon The laterals unlike the V-shaped double bundles of the midrih arc always endaleh and sinee the strands lignify basipetally in very yOllng material till independent developshyment froll1 that of the root pole is sllggested by Siler (0) fOt illetilliln Howeycr it uppears that in guayule the two ateml tmces split off frol11 the median trace (the V-shaped double bundles) near the base of the hypocotyl a condition which according to Dungeurd (1) holds true for the Compositue in general

The fOllr bundle~ of the luwer hypocotyl (pI 4 B and fig 10) will be designated for coneliilllcl as A B C and D About halfway up the hypocotyl these foul bundles idln and then split to form eight uundles A alld Aa 13 and Bn C and Ca D and Da (See fig 11 tt B) jirom here on the course of the cotyledonary traces lind of the traces of the eplcotl that supply the first two fohage leaves may follow one of several pattellls

PTTEIX I (fig 10 A )-Following the differentiation of the eight strands bundles All and ea widen and giye off bundles Ab and Cb and tllln mc)( Ollt into the cort(lx where they divide to forl11 the lateral imces of the cotyl(dons (pl 5 A) ~tllidl(1s Ab and Cb fork again splitting ofl bUlldles Ae and Cc at the Same time bundles Ba and Da widen and split oil llllndl(s Bb and Db BUI1l11es Bb and Cb fuse to form the midrib of the fir~t foliage lenf while bundles Ac and Db unite to f01111 the midrib of the se(oll(l leaf The two laterals of the first foliage leaf are formed by bund Ie Da and Ab whereas the luteltlls of the s(tom11laf anfllll1wd hy bUl1lllls Ha alld (C (pI 5 lJ)

lA1TEHXII (fig 10 B)-This pattern diffrs ftOIH the plliolls one in that oundl(s Ac Hnd Ab as well as Cb and Cc aIpound gien oft hom A und C dilpct instpoundad of from the two latellll Aa and Ca

PATIEIIN IiI fig 100) -_ccordi ng to th is sdl(llle lmndlpounds A B C and D split 0112 bUlldles each so that a eross (etion taken a little beshylow the eOt jelionary 110(( shows 12 bllndles with the IIndhided 2 lntcmls Daand Ba aIL(I(hc out in the (ortex Ill( middbs of the first 2ieaws arC fll~ioll bllll(lles as in tIl( other 2 patterns

Lloyds I((Ollllt (If til( COIIIse and c1elinltion of tilt leaf traees (4) is fundamentally at ltariall(( with lIll of these pathlI1s Rinepound his conshyClption of the ori~ill of the latplHls difhl- 110111 that of Dungeard (1) with whom thi author COI1lUr a certain disagreement i to be exshypected

bull

bull

bull

bull

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

PLATE 5

bull

- - shy

-1

bull

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

bull

bull

bull

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

13 MORPHOLOGY AXD ANATOln- OP GAYULE

middotIGUU K-(ls oStetioll thlough 10(1 h~IIO(otyl showing 1(Rill (tllal OIIJlOsitl til( fOUl phhWIll gIOIJIJ Thl plOhJXtIl poillts alp lltttlIIl (pll la~lrs (PlltzlId fWIll the l)(lie~ell X 47()

The plimalY esill callaIs anll filwls in tllP hvpocotvl arise ill the sallie manlier as ill the Loot There a(~ cOllllllOllly fotll resin canals ill tl( 10(L trallitioll llgiOIlOIllmiddot opposite eaeh pltlmll1 g)OIlP (fig S)

bull Tlw gLonps of primary fibers also fOllL in number lIsually adjoin the

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

14 lECThICAL BULLETIN 842 U S DEPT OF AGRICULTURE

endoclennis (pI 3 B) Lloyds own illustration (4) shows the fibers bull next to the endodelmis so that it is difficult to unclelstnnd why he 1I1gues agaillst their pericyclic orinin

Periderm is initiated in the seaPud layer of the cOI-tex 01 eyen mOlC

centrad (pI 5 A)

Fwnu l-(IOgt (ltioll thlull~h a[Jitul Il~ion of picot1 I)ing dilTrllntiation lit hIIE 111lt Hnd IPin lIl1al 5U Nllt tlial 11IlI( 11( 11lt1 I(gtill (allll ill tbe pith

EPICOTYL

Ti~sur ditTrlrntintion in th( l1ppN (pic0tyl i illl1stratr(l ill figull V Tilt tOlttx is from foul to fin Ilyel thick and i- not sepalated from the -tlmiddotk by a ddinitc (nclodclll1is T11cre ale present eight resin

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

MORPHOU)GY AND ANATO~Iyen OF mAYULE 15

~ -

) = sect

a ~

laquo

~ 0 -

~

qg - ~

g tshy

shyif

E ~ -c C

rg

~ c ~

sect If

a ~ ggt

c I

G 8

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

16 TECR1YICAL BULLETIN 842 1 S DEPT OF AGRICULTURE

Camiddotmiddot

~IGLru~ 11-A Cross spetioll thlol1gh siple of hm hYloeot~l showing till widenshying t)f 11IIndlt A ami thplp1itting otI of All (SII tig10 A pattern I) B Cross s(~tion ncar ulllJer h~1I0cotyl showing the splitting off oJ additionll lmlldlcs X 400

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

17 ~roRPHOLOGY AND ANA1O~IT OF GCATLE

FHURE 1- Dinglmiddotn 1111 IlH ic- lt1rll wing of tlOISi 1(1 ion frolll bns of l-yarmiddotold hoor r titllI plUIl llor in InllllImiddot X (i0 middotnli ElltlntllIlli JlI curt IIrilllalmiddotY ltorlx ill ((III 11Imiddothuar) tortieal CIIIlIII PI t Jllrie)middotc-li~ Jiulrs pll phloem x xrlelll II f llitlt tillI ) 1(11 pith (allal IIT IltriIlIJJIl B COUlparative secshytiOIl from IIIJlidly grmiddotowiug plaut riel ill rubber X 00

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

18 lECBNICAL BGLLETlX 842 t S DEPT OF AUlUCCLTGRE

canals in InlOllS stages of development belonging to the median 1111d bull Inttllll traces of the fhst two foliage leaves The mode of Oligin of these truces is shown ill ligures 10 and 11 and plate 4 Some of the traces 1l1e nlready split off in the hypocotyl simllltaneous with or immediately following the diffelcntiation of the lateral cotyledonlllY supply

FtGUlU lJ-Dingrallllltalic drawillJ (rv1II lIa uf fifth illh~ruode 01 slelIing shoshyill) Ieluthp 1)4)8i(ioll nf IPH( UHttmiddotS Ipsill (Hllal pelkyclie Hlld Ilith fihrs MI IIwtiian trate of Idest haf LLI hft IHteral trll(l of oldest Itaf RLl right latera) tnlce (If oiliest Itaf pt( TIIP ill 11(1 IIl11l1hpl 1 In Iii ar (nnilt(nthc b1lllIi lIumblIS malket duwlI 1111 (01lelliell((1 and without morlllologkal sigll ifiea lieI ~otc thut not all 15 hl1lullts 11111 separurelr tluongbout theitmiddot lItire course

OEFIXlTl 511)[

The ~b1II tip of a setdling examined toward the end of the l~ltatin Sla~on ditfcr~ from the epicotyl in hl-ill~ (esin canals in the pith lPI 6) and fibrous caps around the protoxylelll in the region of the plrinllltlulur ZOIlC The number of blllldies also is lllger nnd the peliphcJalrows of cortical cell arl distinctly collenchymatolls There is no definite endodermi but the starch sheath shows lip prominently

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

bull

bull

PLATeG

CnJ -- -ptLiull Ihrtlugh tpieal ltg-iOll uf tllll --ttlll ThlliP- 11(111 prilllnry (lwtil1 Iallnl nlld I pilll (11111 Ill (1111 -11 j lIIIIIII~II1II1I1 llltI Ill lpi shyt1(l1ni- j- i1(IiI- IPIIIItI willi hair lU

bull I

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

- -

redmiud BuUctln SmiddotU U S Department of Agriculture PLATE 7 bull

bull

~~ shy--

~ ~ g ~ Fmiddot=~

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

-l amp ~ cgt ~ if = ~ ~ I

~ ~]

i i1 2 gt ~ ~

llQS are very narrow but Ihue out funnellike in cClItex X 2) l11atous The resin canals lire greatly compressed tangentially t iaIly after radial divisions bad ceased X 72

bull

lJ I~nlalgpd view of cOllex All old phloem has become sclelellchyshyThe vascular ray cells of the old phloem lire also stretched tangenshy

1l

~ m (Xl

A Iartial cross section of old stem of field plant Note massive perirltgtIIlI broad cortex and annual ring structure in xylem Vasculal

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

=

[ tgt c ~ 0gt

-bull f=

f ~

~ 2

~ n =shyC

-I COII section through xylem of old stem If fidll-glIwn llanL VuSIIIUI ra)s ure unifurmly ImlOw xrlem ill general is illdistillctJ~middot dilIulic lurous X 100 lJ Ellllrge(] view of xylem showing shape of vessels and libriform fibers X 420

U r raquo f11

0

bull

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

bull

bull bull

MOHPHOLOGY A~D A~ATO)lY OF GCAYCLE 19

whcn fresh stem sections are staincd with iodine (fig 12 A) The epidermis is densely pubescent Periderm development lUIlY set in at different levels orten the firth internode Its origin is hypodermal (pI 7 A) There n re present 11 resin canals flanking the oldetmiddot bundles (fig 13) but medullary or pith canals are wantin~ as yet they arc absent rLOm shoots of less than 10 intelnodes n tact already menshytioned by Lloyd (4-) Vllen they arc presellt (pI 6) their llumbeL varies bitween 2 and 6 with 5 as the most common IHunbel This is in alleenwnt with the type of phyllotaxis that shows It prevalent dishyYergence of 25

The COlllse and deLivation of the leaf traCtS is not nt a11 uniform The nwdian trace or a given lea lIlay be lL fusion bundle as in the (pieotyl OL a bmnch of a larg(L bundle running independently fOL as many as foul internodes

A eross section through the fifth internode of 11 shoot shows till lelatiyc position of the median and latelal traees of the first five leans (fig 13) Fifteen bundles ari present Eight of these lepleshy~en-ting the median and lateral traCtS or thi older leaves have calls or primary pelicyclic fibers above the phloem and three have in ad( ishytion ptIime(Jllllary caps (bundles L 611 in fig 13) To be sure not all the 15 bllndl(s shown in figure 13 run separately and independently throughout their entire course Some anastomoe allll ruse and others split to form the traces of later departing leaveR Of interest is the structure or the xylem of the oleIct leaf traces In these the xylem is cOlllposed altogether of small spiral eltments eontlasteLl with the large xylem cells in the adjac(nt younget bundles (pI 7 B)

ANATOMY OF MATURE STEM

GENERAL STRUCTURE

A cross section of n stem of hunest size (pI 8 A) shows u dense woody core and a broad cortex limited extemaHy by an irregular mllssi ve periderm

The wood is made up of a series of concentric or excentric rings each of which represents in nOmally developed plants the anIlual 111C1eshyment of wood Stems frequently show a banded appearance in cross section The bands follow the general contour of the annual rings but they Ire not identical with them In general the annual rin~s are poorly defilHd and wry narrow Frequently they vary in willth in diticrin parts or the circumference of the stem at a given level Also in response to aunormal distribution of rainfall additional annual rings Illay bemiddot fornwd This makes the practical value of rings as indiea tOIS of age of pIn nts middotwry uncprta in

The pith is very small and although it enlarges considerably in older plants it is usually less than 04 mill in diameter In old stems the pith may become in part sclerotic

The cortex comprises all tissnes outside the cambium It consists principally or StcolI(lary phloem both funetionnl and old together with vestigese or the primary cortex Under low magnification it apshy

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

--

20 TECFL 1 (I IllLLETL S-I2 r 5 DEPl 01 AGRICULlTHF

bull

bull bull

A

- ~-_ -shy

- - -~-==-~~~~~~~

B

FIGURE 14-1 Diagrnlllllllltic drawillg t1uollgh secondary (orl(x (If lar)( stt111 X 40 p P(Iidprm ~ H(illHaIT resin canal ~ IPOlll) of IhrellshyrhYllIn (l 1111 Icrin ph()(IlI E xyl(III B Drawillg of SIlluary COIlex of Inrgp 8C((IHIIlT ImiddotOOr X -to Note tlmt the ((l[l(X is Ilvt Ilcarir as wide as iu thl~ Itill thut rhl g1OllPS of selmiddotrtll(h~middotlIJa an flwpr aud the phklllll grollP are stlNehlt1 rlugllIrinllmiddot ratlwr hull radially_

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

T laquohniral Bulletin 8~2 U S Depart nt of Alriculture PLATE 10bull

Various rnltS of ypsels obtained by maceration of wood with nitric and chromic acid (10 percent) X uOO

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

PLATE t 1

bull J

=

~f sect

~

shy

-=

bull

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

21

bull

bull

bull

MORPHOLOGY um AHOMY OF GUAYULE

pears to he made up of irregular concentric layers of fibers and resin llInals nltelllllting with one another lind embedded in parenchymutolls ray t isslic (pI 8 B ald fig 14 A) In the regilHl of the cambium the phlo111 (onsists of thin-wlllled tissue containing usually one ring of resin cnnals

The protective corky ]aym 01 pCIiderm is massive ami irregular often showillg deep notchcs in trallsverse stem sections and irregular tisSIIIs ill SlIlfll(p it 111 nllieties high in Iubber the pelidem is uSlIlIlly thin Lentk~(ls Ilre faidy abundallt Deep cracks and plnces of injlllY lire often marked by cscllping Icsin thut collects ill drops 011 the wound

XYLEM

Tht xylllII i indistinetly ditluse porous with the pores oftln grouped in II mlll1llll to silllulatl a Iing pnrous (ondition (pI 9 A) Thl pOles all banmiddotly isibl to the lIakld eYl and the asculur rays IlrB

illisible 011 both (ross alld longitudinal sections The pores 01 nssels are faidy nUllllrous round elliptical or someshy

hat allgulllr olitary or in lIIultiplls of two 01 mom (pI 9 B) alyin~ in ~izl from 1l~ to 54~ Ypsstmiddotl 1I1lIIIhlrs un ltylindrical or fu~if()rlll to ilIIgulll~ ill shape (pI 10) with 01 without ligular proshyj((tiolls b(yond the perfolatiOIl plates from wry short (75~) to nlltliulll long (HI)) Pplfolat ion platts ale horizontal 01 obliqtll the l~dollltion lltilllpil I~ahral walls haye IIUll1eroUS slightly altershylIahmiddotl allIHlgetl pits bOldels bllHl(lIy tlliptical holizontul Ot sli~htly oblique The latlral walls ill all lltlltels hu( tertiary thickening OldlI YesHmiddotIs sOllletimes (k(lop tyloes alld the lumen of others llIay tontain gum J)lu~sll

~o()d lalln(hynu is spurse illdistinctly t~Iminul and parutracheal hu t 1IlIl f0111I i1Ig COlli pltmiddottl shla th 11l0Ulld -esslls cells 11Il llongated lintl usulilly POillhll Pits Sl11ull simple numerous on vertishyeal wulls ill cOlltad with (sslls but wUllling on wall bOlderinr fibers

iiben are of I ibli fOIl11 type f01111 ing ground mass of WOOl faidy unifolm in tJllllswr8e se(tioll tnplIillg gradulllly with smooth toothe~l OL forked llIds They ure rdutilly sholt (less Ihun 2)0) walls wry thick lumina 10111(1 deltoid elliptitnl 01 slitlikp in tlUIISVelse section Pits not numelolls bordered with oblique slitlike apeltmes

Vas(ulal rays ILIl c1oslly spt alld IIUIIHrOUS uSllally Ttry tall slightly llltelogllwoIIS III ttanSlrSe section the ray (ells llre rashydiully (Iollgaltmiddot but Yllliabll ill tUIIgelltial scdion two to fOlll cells illl at middle mlllginaleells as well a body cells an~lIlal elliptical all (clls IIIl1lilllll thick pit iIlIJll~middot lllld Ylry IIl1n(IOIlS In wmiddotry old steJII the 1Il0st cClltllld pH rt of t Ill rays llIay be 1ign ified wholly 01 in part

PIIIOE[

_OCTln 11I10E~1

The fundional (condnJY phlo(111 of guaYllle like that of many othet wooliy plants is a lompllx tisSUl made up of a number of cell typts nil of which haw a lOllllnOIl origin ill tlIP camhium The cells of the latttr are bdck-shaped ill tLan~erse section and fusiform

22 TECHNICAL BCLLETIN 842 U S DEPT OF AGRICULTURE

in tangential section (pI 1111) they are arranged in definite horshyizontal rows In radial section (pI 11 B) the cells are very llaflow bull and the end walls are square 1he rad181 walls aloe mud thicker than the tangential walls Ilnd appeal prominently beaded (pI 1111) that is showing abundant pitlike thin spots

The elements that comprise the secondary rhloem are sieve tubes companion cells and phloem parenchyma Ihey form more 01 less uniform rldinl sectOlS (pI 12) 1 mdiating centrifugally from the cambium and separnted from one another by rays that are continuous with the vllscular ruys of the xylem The tiered arlllngement of the cambium cells noted above is maintained to a certain extent by the sieve tubes and phloem plllenchymn (Us (pI 11 B)

I

shyr

FlGrRE Ifgt-Tnngcntial ~Ctitlll th ngh lIhlcwllI of root showing siele tubes COIllJlIllioll ~~lls 1I1ll1lhlO(mi pUlmiddotellchylUu X iOO

The sie-e tubes with their compunion cells make lip the greatet pumiddott of the aetive phloem They occur in glOllPS of two 01 more lwd are bordered radiully by 1I11gel plllenchyma cells (pI 13 11) The sieve tubes of the stem are JlIther slllall compared with those of the loot and are not always readily s(pamted flOI1 the companion cells in transverse section The end walls of the sieve tubes ale someshywhat oblique 01 the si(Ye plates are strictly transvee (fig 15) There is commonly OIl(gt sieve filld with numelOIlS small pores but occasionally two siee fhlds are obstlved and ill sueh euse the end til is steel)ly sloping The lateral walls of the sieve tubes are withshyout lattIces

bull PLATE 12

J

bull

bull

r It ( 1~rt tlJllll1i tO fol1l-- lIf hmiddotthp pl11lt11l1 -lptlratt1d by 11111 -I TliI Idifllln Inltrh~IIJ1 (I I In- lI(I1~ilith~t h~ tllPll 1111 til lOlllllPlll Hlltl

1 p Tltt~ ~ pwPt~i Ittwlrtl flltl Illt (11 th illl~traliflll llld --illltp III

middott It latlr(lflUtl t-I ~ p1 IItmiddotlnllHll pH Ihp hmiddotfI th- nlllady hal 11Iltllll t d iul llt 1 ~-I

bull Icthnicul13ulletin 842 L S Department o( AMrlcutmc PLATEt3

bull

bull

I ElllII)I1i partial dlw of plIt 2 lhwilll in )tlatlt lI~tail tho ilI tugtS with twit (lIlpaUioHl (middottlI alld lhlollII )IrlIl(lrUUl X I)n II Hadial tillll Ie ~OIIIl hut allla(l~ imlllin lhhl1l If lInt ~(l(l I hI llolllill(lIt hillilllikl pitlinl (If tilt radial walls Sien wues ami cOlllpallion cll1s allIII11y all ltI1I~11t( 00

PLAl E 1middot

bull =

bull or ~

~E ~ ~f

=

bull

PLATE 15

bull

bull

t lllId 1lilll1 IhlOI1h ((in phlplil lIr old IIII XII lhal Ih (1 in phfotlU lPjllmiddottmiddot l

l lll I -U ~Tu( It ltHItIIHPIII - 70 Il (lfI- -(1011 T lItill1~h (lIl1lrilllll 1111[ oHII (lhlllllI1 Idoll or I ttl hll 1llllioll of Ilill (lIlal I ltillllll EPdhili If of (11111 aInu 11inllly 011 lallihilllll JiU

bull

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

bull PLATE 12

J

bull

bull

r It ( 1~rt tlJllll1i tO fol1l-- lIf hmiddotthp pl11lt11l1 -lptlratt1d by 11111 -I TliI Idifllln Inltrh~IIJ1 (I I In- lI(I1~ilith~t h~ tllPll 1111 til lOlllllPlll Hlltl

1 p Tltt~ ~ pwPt~i Ittwlrtl flltl Illt (11 th illl~traliflll llld --illltp III

middott It latlr(lflUtl t-I ~ p1 IItmiddotlnllHll pH Ihp hmiddotfI th- nlllady hal 11Iltllll t d iul llt 1 ~-I

bull Icthnicul13ulletin 842 L S Department o( AMrlcutmc PLATEt3

bull

bull

I ElllII)I1i partial dlw of plIt 2 lhwilll in )tlatlt lI~tail tho ilI tugtS with twit (lIlpaUioHl (middottlI alld lhlollII )IrlIl(lrUUl X I)n II Hadial tillll Ie ~OIIIl hut allla(l~ imlllin lhhl1l If lInt ~(l(l I hI llolllill(lIt hillilllikl pitlinl (If tilt radial walls Sien wues ami cOlllpallion cll1s allIII11y all ltI1I~11t( 00

PLAl E 1middot

bull =

bull or ~

~E ~ ~f

=

bull

PLATE 15

bull

bull

t lllId 1lilll1 IhlOI1h ((in phlplil lIr old IIII XII lhal Ih (1 in phfotlU lPjllmiddottmiddot l

l lll I -U ~Tu( It ltHItIIHPIII - 70 Il (lfI- -(1011 T lItill1~h (lIl1lrilllll 1111[ oHII (lhlllllI1 Idoll or I ttl hll 1llllioll of Ilill (lIlal I ltillllll EPdhili If of (11111 aInu 11inllly 011 lallihilllll JiU

bull

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

bull Icthnicul13ulletin 842 L S Department o( AMrlcutmc PLATEt3

bull

bull

I ElllII)I1i partial dlw of plIt 2 lhwilll in )tlatlt lI~tail tho ilI tugtS with twit (lIlpaUioHl (middottlI alld lhlollII )IrlIl(lrUUl X I)n II Hadial tillll Ie ~OIIIl hut allla(l~ imlllin lhhl1l If lInt ~(l(l I hI llolllill(lIt hillilllikl pitlinl (If tilt radial walls Sien wues ami cOlllpallion cll1s allIII11y all ltI1I~11t( 00

PLAl E 1middot

bull =

bull or ~

~E ~ ~f

=

bull

PLATE 15

bull

bull

t lllId 1lilll1 IhlOI1h ((in phlplil lIr old IIII XII lhal Ih (1 in phfotlU lPjllmiddottmiddot l

l lll I -U ~Tu( It ltHItIIHPIII - 70 Il (lfI- -(1011 T lItill1~h (lIl1lrilllll 1111[ oHII (lhlllllI1 Idoll or I ttl hll 1llllioll of Ilill (lIlal I ltillllll EPdhili If of (11111 aInu 11inllly 011 lallihilllll JiU

bull

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

PLAl E 1middot

bull =

bull or ~

~E ~ ~f

=

bull

PLATE 15

bull

bull

t lllId 1lilll1 IhlOI1h ((in phlplil lIr old IIII XII lhal Ih (1 in phfotlU lPjllmiddottmiddot l

l lll I -U ~Tu( It ltHItIIHPIII - 70 Il (lfI- -(1011 T lItill1~h (lIl1lrilllll 1111[ oHII (lhlllllI1 Idoll or I ttl hll 1llllioll of Ilill (lIlal I ltillllll EPdhili If of (11111 aInu 11inllly 011 lallihilllll JiU

bull

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

PLATE 15

bull

bull

t lllId 1lilll1 IhlOI1h ((in phlplil lIr old IIII XII lhal Ih (1 in phfotlU lPjllmiddottmiddot l

l lll I -U ~Tu( It ltHItIIHPIII - 70 Il (lfI- -(1011 T lItill1~h (lIl1lrilllll 1111[ oHII (lhlllllI1 Idoll or I ttl hll 1llllioll of Ilill (lIlal I ltillllll EPdhili If of (11111 aInu 11inllly 011 lallihilllll JiU

bull

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

23

bull

bull

bull

)IOHIIWLOI- AxD AxAT(l~lY OF GLTL

AlthOIlh hPpral hip( IlIbps mar abut on (lch othpr there is norshylila Ily Oll~ eoIII pn II ion ((II to a sit t 111)( (xt(utl i nl ti( puti IP IplIlth ()f I Ill ilYI tulw IIPII1(lIt to wld(h it is adjatpllt (IiI ) AeeOldinl to illtmin en ill( Hil lubp of til( COl1lpositl1 i1It of I 11111(11

lalllI lrallSplSI dialllltel than tilt lOIIlPlllioll IlIIH but Lloyd cn holds Ihat thi i 1I0t trill of (LItli(1l iUIII Aeeonlilll to Lloyd lhplp is hilt littll llillPlllIel ill tTallSprH diallwt(I of tiIlSP till (Olllshypallioll (pil J(il1l nllloly fusilollll and t1(n~f(JIc thiekft at t)( lIli(ldll whil( tlumiddot 11(1amp of lOlllse is trlle of the sin l1tllIent- ]lOWPI ill tlH ill(titratiom lPporhd in this bllllllill then is a dilltI(II(( ill iZI bltwoNl~thlHl two (I(IIHnl and dthollUh this dillIshyI 111( is lIot PIY pIOnOIlIllImiddotd ill the phl(wlll of thp tllII It is (ollspilUshy(lll- in tllP ]lldollIl of ti( root as will h( shown lallr

Ill(gt phlotlI palpnchYll1ll 1l1I an of till (lIl1bilollll Iypl alHl in tanlllIlial sedioll look I 11I11(h lik( Ihl (lIl1hilllll (ell 11011

lti(h Iht an dlrinl Thl art 1)Iofll(ly pittld radially with II( pit 1I11allled ill illlikp glOllpS TIll (plls pnJargl as till TO old(I hut Ihl alls do not thitk(n until tolld the IlHl of till ~Iaon lhtIl is nil dillPlillP 1ll1t11I tIll phlol1rI PlItIllhYIIIl lells 111lt1 ill (h~IIII(hnll initials simp lIIost of tl( ((ll an poillitd alld 1lnlllall thilkllI alld lignify 1111 IHIIlllChynltl (llls slIlIoulHling till pitlttlial lawl of till nill (anals (ontaill lalg( stal(h grain Ii kl IIll Illdodllm is O((asiolllllly sta Ith isfoulld ill the PIIIIlshy(hYllla l(lls i midl tlll 11 dodtlI II is Home illWS f01ll1 iIl~ sillgle lI(ia I lII~ along till lanI of til OUllllllOst glOIlP of fihpls lOlllwdin 11ll (lldodlllIlis with Iht jaeklt ((lls of thl fil~t sllondlIY llsiil ea 111 1-

TIll Ily tislll of tIll pldo(m i lontinuous with the Yaselllal 1lyB Ill thl xyhlll (pI R A) Th( ray 111 in tll hllilllling as widl as tIll Xyhlll rays hilt 111l~ -halply ill(IIlH ill width outwardly (pl l~) Thi~ idllIillU of tht 1 is Oil nsltlt of ill(I(aSl ill l(ll size toward tlll 011111 Imi of Ill( 11 IS wIll as HlIllC inITtac ill tllt llllmb(middot1 of Iplls Tn a (10 ~teti(11 of a stllll the ray (llls aplwar dongated radidl hilt distally tltelt i- Illuch tallgential stntelting to (olllll(nshy-atl fol tIll in(Iasl in (illlIl11fllplIl( laIlHlt hy thl (nlIIgtt (limllshy(tll of tIl axisltl langlntial sdion till ray (Ills aplwal Iolilld Ill I IIgllla I (pI ll _1) with (hp IlIalgimd (Ill wmally JaIII alld 111(11 lolIUat(11 Thl lallUlntial wall~ all Illail pitted the pit II1lI1glti III lienlike glOlIPS

SEGOXUAHY HESI= ltIS

Ihl ollloglll of till SI(OIlI1aIy Ilsin (alia I lias h((11 in in lt1ltail h (o- (j) and Lloyd (4) Ihl allal an slhizogllI(lll~ ill olilill alld in thnt 1lSPIli 1llIhll till PlilltalY (ollilal alld pilh (allal T11I In dlli(d dilf-etly 110111 thl (a IlIbi 11111 (pI Iii B) Thl IWo (Ill

laII plit wy and thl talllllItially litltlIld Spall glldllall~ blshy(WillS phllieal TIll ((l1s bOI(tlillg tlll (alia I f011II thl epith(lilllll 01

S((IlIOI ltYlI I ItIY all 11Ii(k-shqwd ill (TOSS SI(t iOIl alld tlolIgatld Il(talllldal lungit Ildilllly alld all (ily 1l(olIizld by tiwil densl PIutoplallIit (IIIII(lIt alld lalgl Illl(ti Onasiollllly pliol to tltl fOIIlluillll of 111 (allal thl ltpithllial illitials diidl IJlIil1 ilia lly pmshy(tleillglll ddil iOllallayl1 of (1lb fhi 1I)ll Ja(ks tltt 1Il( lto llallli(

24 IE(HXICAL BlLLETIX 8middot12 L S DEPT OF AGHlClLITHE

content of the slcrtlory layer but difren flol11 tIll alljaccnt phloem purelHhyma cells The fully dlHlopld resin canal is usually sphershyical it 1II11Y Iltain this shape or beeollie (ollll)Iessed blllgentitlly us till phlollll bl(OlllIS illaetin allll seilrPllchYllla deelops Acconlin~ to Lloyd (4) till eanals beCOllll frequllIt1y closed by an ingrowth of t i-iSlIl that resllllbleR a bUllch of glqWS SlIeh lxllllsin~ pseudoshytyloSlS dlelopnllnt has not been obsened in I he matminl aailablp Jor stlldy but ITiehomelike stll1ctures proliferuting froll1 the cells of the seCIttolY lay(I have frequently beln noticed (pI 11 B) The jaekft of palllIehyma eells sUllolllllling till secretory Iayel of the (lIllal is frolll olle to se(~ral cdb wiltit Thesl (ells ale filled with stalch but contain little rubber liS willlw shown later

IXACTIF PIILOE[

Cessntioll of act iity in tlw ~e(ondary phhwl11 is gmdual In the yuulIg slllIIS tIll si(( tlliJlS lIlay fUlIction for a single sen son only hilt tI( phlollIl of tlH Itrg-e brandlts may retain a llOrllluI structure for two (()llIplete Stasons t pI 10l A) ~ ex((pt for the formation of callu d(polits onL tlH siHe platts Sometimes toward the ellll of the growshying Reason some of tht phloem parenchYllm cells or scleLenchyma initials U(eOIlI( thick-walletl and lignify (pI12) Lignifieation of tht phlotm pnJtllchyma is llmally CllItlllll frol1 the outll mUlgin of the Slaso II i gl()~th hilt in IIIHttIiaI whelt th~ phloem remains StJuduLal1) l1n(hangldtor two SeHSI)1lS sohtalY Itg-nlhed cells 01 small Islands of titilk-wull(d fib(rs may occllr sporaditally in till millst of otherwise llOIIII111-applaring phlolm The phlOlm fibers yaly greatly in size a nlt slla pC sOllie ai Iypic-al pointtll fluPIs otllllS are bload spindleshy~htlpld alld SOllll hlle I1IDle or less square end middotwalls The phloem filllrs aI ill thiClmtss bptnln 15ft and 701 and in length between IGOt and G401 The IWlipl1lral ClIS of the Hrst ring of fibers are 11111 lIy (IY lal~e and nUlle like stone cells in Character having been dlriwd from cdls of the ray tissll

With tll( IHognssie enlalgement allll1ignificntion of the fibrous ehlIwnts t h( SilYl tllbts and eompanion eelh nre crushed The colshylapH of thpSl pltmpnb is IIslIally so complete that the cIushed cllls an npnsllllpd only by an illlgular hl~lll of wall BllbBtance (pI 16 B)~ hut til( fihlls (I II Ill to oCupy tht (lit lll alta of fOIllelly aetive phloem neglIi~ahl( in tangIlItid Ntioll by d~lply staining anastomosing bands aga inst a backg-rountl of slIHlll-cclled yascuiar ray tissue (pIIG)

PERIDERM

The Iwritelm Ot (olk c(llIsi-ts of Iwo layers of tissue phellogen and (ork Xo plHllodtlm is fOIlled to~nlld tIl( insidl Tlw phelIogllI or (olk (ambiull alisps in the hYlgtodllmis (pI 1 A and pI 11 A) ~()IIItilllls rhis laYlI diidts ollly ontp formillg a slIJwlficiaIlwlidpll1l hill a slIbhypotil1lIud layer takes onl the funetioll of till pl1llIoglIl Till (olk (Ill 1Jl of till (()mll~l1 type m~tdl lip of th~ee la~els~ h~lt til( walls IlllItllll (piliI tlUII ~II(( (ork tISltUP IS Ielatlely llwlastll i IH p(lidllIIl tll(lops lIa lIow 01 (11PIgt (rac-ks a tIl( stem illtreases 111 diallietpr (pI 17 11) ThlsP fiSSIIIP in till ((1Ik lIIay (xtpIHl as Illep as t 11( IWlipllllal Iesill (allals (allsillg till llsill to ooze Ollt alld coiled in slIIall dopllts 011 till Olltl -urfale

bull

bull

bull

bull

bull PLATL 16

bull

bull

PLATE 17 bull

1 lruss (lttiOll tltlough ~()lllg tllt hl)illg hnHllellIlaL unglll f Llerid~lIll X middotHlO II (1 (1 i11 through olll llllidrlli of root -lute the dPl (laek ill th lturk X 100

25 MORPHOLOGY AND AJATOMY OF GUATULE

c

end

~middot~middotmiddotmiddotmiddotmiddot1~middotmiddotmiddot middot sec c

middotmiddotmiddotmiddot xyL

A

o 00 000 o

o o

o o 0

o cfoOO

PlGlltE IG-_L Viagranllllatie tlrawing of lt10 Sldion of 1a1IIa 1 root 27 Illlll ill (iaIllPlPr PCI Illriderm Ill e primary ltortex clld endodennis SCt tmiddot

~PlOll(lalY Illrtex cyl Xyl~lll B Drawing of hllgel root 18 Ilun in dianlltel

26 ECHXTCAL BlLLETIX S-I2 r s DEI)I OF ACRIClLTlltE

The original sn)1lIfieial periderm may persist fOl the life of the plaut when grown in a commercial plantation In its l111tural habitat ll(re plants toml11only become older cork eambilll11S llIay be formed gtrogns1iwly inward gradually tutting off all wstiges of primary cortex Quite oftell lIew plHllogell layers c1eelop internally in 10shy(alized ngion~ cuttinl out shell-shaped layers of primllry and periphera I s((ol1c1a ry (())-tex Such reliona I deep-eated (o~ (1e(10pshyIlHnt is quite (OIllIlIOllly tIl( result of wounding aud is therefore~ met with elm in young stelllS

ANATOMY OF HOOT

The Oot system consists chidl) of Iona medium thiek and thin Jatlrals lt1i llging at right ang-Ils from the taproot (fig ~) The roots are ypllow iII eo101 a lid the smfnceis mottled or roulhenNI by shaIlo lonuitlldinn 1 fissul(s

Cross spdiolls through slIch roots exhibit a hard pith1ps woody (He alld a broad cortex ploteclPc by a mnssie IWlidenll that is mdishyall~s(lllelltwl hy dllP ela(ks (fillG A B) The relatin thie-knlss of tllis eork la Cr is not e()JTllatld itll the diallwtlr of the root bping pr()lllin(I~lt ill thick lalerals as well as thin hl-tiarifs Onl)~ fibrous 10015 less than 15 nun in diallleltr ll(k a periderm but (lOSS(S5 a (hollSe cOelin~ of root hairs tllqrid and functional up to (lit in~(ltion point of thl rootlet Oil a lalg-lr lahral or P(11 the main r(IOt Th(se apparently lon~-persisting- root hairs liould facilshyita h the rapid absorption of watpI eyell from uperficially wctteel soils

Thl wood is (I hard the ((ntml core corresponding in size to tlw pith of the stelll bull is espteial1y cpnsl (pI 181) and frolll its l)(riphery the YllSelllal rays an sepn radiatin~ toward the COl-tCX

The lOIhx i lllassi l but lIot IHll dy ( bmad as in the stel1l (fi~ lmiddotL 11) It is made llP of (Oll(lntli( Inyels of resin callills and fibers pntbeddetl in l)lrenchymntolls ray t iSS11l

XYLE11

Sinl till elll1Wnts making up thi tiSSH( are qnite similar to those (If thl -llll1 n ddailld le5erip( ion will not Ill ginn

TIlt xI(I1 i- indi inetly ditltls(-purolls with the pores Ie nnshyI1WIOllS than in till stllll xcppt ill th( l(liull 01 thp tellt ml cme (pI h IJ) Thl middotl~el an frequently tlTallg-ed ill hort mdial rows t II at oftl1l hOI(ll on til( -a-eulnr ray l pI Ill 1) ~ el1c1oin~ blinds (l r fiber The latter form thl poundtottncl mass of the w(Jocl evell more -0 than in Ow 11(111 Ill( ((II l~r( ah-ay thiek-alled and sparsely littNl roml lHllluehyma is paratlllc1ieal and sparse

TIl nleular rays ale fartllll t1plllt and hlOlHI(r than the rays in lllt lllll )Iost of t helll nn (ry tall 0 that 1l111IlY of the prill1lllY llIYi furm llnintllTllptld radii JiOIlI lhl ((lltral l(lrc to the til llliJi11l11

ill til(gt --Hlli till (ortex (onlpri-(- till hand ot ti-slll illtlll1 lallllJilllll alld (olk It (ol1iA of a llalTllW Iilllmiddot of IlrinllllY (ortex 111(1 a broad Zlnl tlf -llolldn ry ph lilt-ill wit II p--riipgt u f i)rilllll ry

bull

bull

bull

bull

bull PLATL 16

bull

bull

PLATE 17 bull

1 lruss (lttiOll tltlough ~()lllg tllt hl)illg hnHllellIlaL unglll f Llerid~lIll X middotHlO II (1 (1 i11 through olll llllidrlli of root -lute the dPl (laek ill th lturk X 100

25 MORPHOLOGY AND AJATOMY OF GUATULE

c

end

~middot~middotmiddotmiddotmiddotmiddot1~middotmiddotmiddot middot sec c

middotmiddotmiddotmiddot xyL

A

o 00 000 o

o o

o o 0

o cfoOO

PlGlltE IG-_L Viagranllllatie tlrawing of lt10 Sldion of 1a1IIa 1 root 27 Illlll ill (iaIllPlPr PCI Illriderm Ill e primary ltortex clld endodennis SCt tmiddot

~PlOll(lalY Illrtex cyl Xyl~lll B Drawing of hllgel root 18 Ilun in dianlltel

26 ECHXTCAL BlLLETIX S-I2 r s DEI)I OF ACRIClLTlltE

The original sn)1lIfieial periderm may persist fOl the life of the plaut when grown in a commercial plantation In its l111tural habitat ll(re plants toml11only become older cork eambilll11S llIay be formed gtrogns1iwly inward gradually tutting off all wstiges of primary cortex Quite oftell lIew plHllogell layers c1eelop internally in 10shy(alized ngion~ cuttinl out shell-shaped layers of primllry and periphera I s((ol1c1a ry (())-tex Such reliona I deep-eated (o~ (1e(10pshyIlHnt is quite (OIllIlIOllly tIl( result of wounding aud is therefore~ met with elm in young stelllS

ANATOMY OF HOOT

The Oot system consists chidl) of Iona medium thiek and thin Jatlrals lt1i llging at right ang-Ils from the taproot (fig ~) The roots are ypllow iII eo101 a lid the smfnceis mottled or roulhenNI by shaIlo lonuitlldinn 1 fissul(s

Cross spdiolls through slIch roots exhibit a hard pith1ps woody (He alld a broad cortex ploteclPc by a mnssie IWlidenll that is mdishyall~s(lllelltwl hy dllP ela(ks (fillG A B) The relatin thie-knlss of tllis eork la Cr is not e()JTllatld itll the diallwtlr of the root bping pr()lllin(I~lt ill thick lalerals as well as thin hl-tiarifs Onl)~ fibrous 10015 less than 15 nun in diallleltr ll(k a periderm but (lOSS(S5 a (hollSe cOelin~ of root hairs tllqrid and functional up to (lit in~(ltion point of thl rootlet Oil a lalg-lr lahral or P(11 the main r(IOt Th(se apparently lon~-persisting- root hairs liould facilshyita h the rapid absorption of watpI eyell from uperficially wctteel soils

Thl wood is (I hard the ((ntml core corresponding in size to tlw pith of the stelll bull is espteial1y cpnsl (pI 181) and frolll its l)(riphery the YllSelllal rays an sepn radiatin~ toward the COl-tCX

The lOIhx i lllassi l but lIot IHll dy ( bmad as in the stel1l (fi~ lmiddotL 11) It is made llP of (Oll(lntli( Inyels of resin callills and fibers pntbeddetl in l)lrenchymntolls ray t iSS11l

XYLE11

Sinl till elll1Wnts making up thi tiSSH( are qnite similar to those (If thl -llll1 n ddailld le5erip( ion will not Ill ginn

TIlt xI(I1 i- indi inetly ditltls(-purolls with the pores Ie nnshyI1WIOllS than in till stllll xcppt ill th( l(liull 01 thp tellt ml cme (pI h IJ) Thl middotl~el an frequently tlTallg-ed ill hort mdial rows t II at oftl1l hOI(ll on til( -a-eulnr ray l pI Ill 1) ~ el1c1oin~ blinds (l r fiber The latter form thl poundtottncl mass of the w(Jocl evell more -0 than in Ow 11(111 Ill( ((II l~r( ah-ay thiek-alled and sparsely littNl roml lHllluehyma is paratlllc1ieal and sparse

TIl nleular rays ale fartllll t1plllt and hlOlHI(r than the rays in lllt lllll )Iost of t helll nn (ry tall 0 that 1l111IlY of the prill1lllY llIYi furm llnintllTllptld radii JiOIlI lhl ((lltral l(lrc to the til llliJi11l11

ill til(gt --Hlli till (ortex (onlpri-(- till hand ot ti-slll illtlll1 lallllJilllll alld (olk It (ol1iA of a llalTllW Iilllmiddot of IlrinllllY (ortex 111(1 a broad Zlnl tlf -llolldn ry ph lilt-ill wit II p--riipgt u f i)rilllll ry

bull

bull

bull

bull

PLATE 17 bull

1 lruss (lttiOll tltlough ~()lllg tllt hl)illg hnHllellIlaL unglll f Llerid~lIll X middotHlO II (1 (1 i11 through olll llllidrlli of root -lute the dPl (laek ill th lturk X 100

25 MORPHOLOGY AND AJATOMY OF GUATULE

c

end

~middot~middotmiddotmiddotmiddotmiddot1~middotmiddotmiddot middot sec c

middotmiddotmiddotmiddot xyL

A

o 00 000 o

o o

o o 0

o cfoOO

PlGlltE IG-_L Viagranllllatie tlrawing of lt10 Sldion of 1a1IIa 1 root 27 Illlll ill (iaIllPlPr PCI Illriderm Ill e primary ltortex clld endodennis SCt tmiddot

~PlOll(lalY Illrtex cyl Xyl~lll B Drawing of hllgel root 18 Ilun in dianlltel

26 ECHXTCAL BlLLETIX S-I2 r s DEI)I OF ACRIClLTlltE

The original sn)1lIfieial periderm may persist fOl the life of the plaut when grown in a commercial plantation In its l111tural habitat ll(re plants toml11only become older cork eambilll11S llIay be formed gtrogns1iwly inward gradually tutting off all wstiges of primary cortex Quite oftell lIew plHllogell layers c1eelop internally in 10shy(alized ngion~ cuttinl out shell-shaped layers of primllry and periphera I s((ol1c1a ry (())-tex Such reliona I deep-eated (o~ (1e(10pshyIlHnt is quite (OIllIlIOllly tIl( result of wounding aud is therefore~ met with elm in young stelllS

ANATOMY OF HOOT

The Oot system consists chidl) of Iona medium thiek and thin Jatlrals lt1i llging at right ang-Ils from the taproot (fig ~) The roots are ypllow iII eo101 a lid the smfnceis mottled or roulhenNI by shaIlo lonuitlldinn 1 fissul(s

Cross spdiolls through slIch roots exhibit a hard pith1ps woody (He alld a broad cortex ploteclPc by a mnssie IWlidenll that is mdishyall~s(lllelltwl hy dllP ela(ks (fillG A B) The relatin thie-knlss of tllis eork la Cr is not e()JTllatld itll the diallwtlr of the root bping pr()lllin(I~lt ill thick lalerals as well as thin hl-tiarifs Onl)~ fibrous 10015 less than 15 nun in diallleltr ll(k a periderm but (lOSS(S5 a (hollSe cOelin~ of root hairs tllqrid and functional up to (lit in~(ltion point of thl rootlet Oil a lalg-lr lahral or P(11 the main r(IOt Th(se apparently lon~-persisting- root hairs liould facilshyita h the rapid absorption of watpI eyell from uperficially wctteel soils

Thl wood is (I hard the ((ntml core corresponding in size to tlw pith of the stelll bull is espteial1y cpnsl (pI 181) and frolll its l)(riphery the YllSelllal rays an sepn radiatin~ toward the COl-tCX

The lOIhx i lllassi l but lIot IHll dy ( bmad as in the stel1l (fi~ lmiddotL 11) It is made llP of (Oll(lntli( Inyels of resin callills and fibers pntbeddetl in l)lrenchymntolls ray t iSS11l

XYLE11

Sinl till elll1Wnts making up thi tiSSH( are qnite similar to those (If thl -llll1 n ddailld le5erip( ion will not Ill ginn

TIlt xI(I1 i- indi inetly ditltls(-purolls with the pores Ie nnshyI1WIOllS than in till stllll xcppt ill th( l(liull 01 thp tellt ml cme (pI h IJ) Thl middotl~el an frequently tlTallg-ed ill hort mdial rows t II at oftl1l hOI(ll on til( -a-eulnr ray l pI Ill 1) ~ el1c1oin~ blinds (l r fiber The latter form thl poundtottncl mass of the w(Jocl evell more -0 than in Ow 11(111 Ill( ((II l~r( ah-ay thiek-alled and sparsely littNl roml lHllluehyma is paratlllc1ieal and sparse

TIl nleular rays ale fartllll t1plllt and hlOlHI(r than the rays in lllt lllll )Iost of t helll nn (ry tall 0 that 1l111IlY of the prill1lllY llIYi furm llnintllTllptld radii JiOIlI lhl ((lltral l(lrc to the til llliJi11l11

ill til(gt --Hlli till (ortex (onlpri-(- till hand ot ti-slll illtlll1 lallllJilllll alld (olk It (ol1iA of a llalTllW Iilllmiddot of IlrinllllY (ortex 111(1 a broad Zlnl tlf -llolldn ry ph lilt-ill wit II p--riipgt u f i)rilllll ry

bull

bull

bull

bull

25 MORPHOLOGY AND AJATOMY OF GUATULE

c

end

~middot~middotmiddotmiddotmiddotmiddot1~middotmiddotmiddot middot sec c

middotmiddotmiddotmiddot xyL

A

o 00 000 o

o o

o o 0

o cfoOO

PlGlltE IG-_L Viagranllllatie tlrawing of lt10 Sldion of 1a1IIa 1 root 27 Illlll ill (iaIllPlPr PCI Illriderm Ill e primary ltortex clld endodennis SCt tmiddot

~PlOll(lalY Illrtex cyl Xyl~lll B Drawing of hllgel root 18 Ilun in dianlltel

26 ECHXTCAL BlLLETIX S-I2 r s DEI)I OF ACRIClLTlltE

The original sn)1lIfieial periderm may persist fOl the life of the plaut when grown in a commercial plantation In its l111tural habitat ll(re plants toml11only become older cork eambilll11S llIay be formed gtrogns1iwly inward gradually tutting off all wstiges of primary cortex Quite oftell lIew plHllogell layers c1eelop internally in 10shy(alized ngion~ cuttinl out shell-shaped layers of primllry and periphera I s((ol1c1a ry (())-tex Such reliona I deep-eated (o~ (1e(10pshyIlHnt is quite (OIllIlIOllly tIl( result of wounding aud is therefore~ met with elm in young stelllS

ANATOMY OF HOOT

The Oot system consists chidl) of Iona medium thiek and thin Jatlrals lt1i llging at right ang-Ils from the taproot (fig ~) The roots are ypllow iII eo101 a lid the smfnceis mottled or roulhenNI by shaIlo lonuitlldinn 1 fissul(s

Cross spdiolls through slIch roots exhibit a hard pith1ps woody (He alld a broad cortex ploteclPc by a mnssie IWlidenll that is mdishyall~s(lllelltwl hy dllP ela(ks (fillG A B) The relatin thie-knlss of tllis eork la Cr is not e()JTllatld itll the diallwtlr of the root bping pr()lllin(I~lt ill thick lalerals as well as thin hl-tiarifs Onl)~ fibrous 10015 less than 15 nun in diallleltr ll(k a periderm but (lOSS(S5 a (hollSe cOelin~ of root hairs tllqrid and functional up to (lit in~(ltion point of thl rootlet Oil a lalg-lr lahral or P(11 the main r(IOt Th(se apparently lon~-persisting- root hairs liould facilshyita h the rapid absorption of watpI eyell from uperficially wctteel soils

Thl wood is (I hard the ((ntml core corresponding in size to tlw pith of the stelll bull is espteial1y cpnsl (pI 181) and frolll its l)(riphery the YllSelllal rays an sepn radiatin~ toward the COl-tCX

The lOIhx i lllassi l but lIot IHll dy ( bmad as in the stel1l (fi~ lmiddotL 11) It is made llP of (Oll(lntli( Inyels of resin callills and fibers pntbeddetl in l)lrenchymntolls ray t iSS11l

XYLE11

Sinl till elll1Wnts making up thi tiSSH( are qnite similar to those (If thl -llll1 n ddailld le5erip( ion will not Ill ginn

TIlt xI(I1 i- indi inetly ditltls(-purolls with the pores Ie nnshyI1WIOllS than in till stllll xcppt ill th( l(liull 01 thp tellt ml cme (pI h IJ) Thl middotl~el an frequently tlTallg-ed ill hort mdial rows t II at oftl1l hOI(ll on til( -a-eulnr ray l pI Ill 1) ~ el1c1oin~ blinds (l r fiber The latter form thl poundtottncl mass of the w(Jocl evell more -0 than in Ow 11(111 Ill( ((II l~r( ah-ay thiek-alled and sparsely littNl roml lHllluehyma is paratlllc1ieal and sparse

TIl nleular rays ale fartllll t1plllt and hlOlHI(r than the rays in lllt lllll )Iost of t helll nn (ry tall 0 that 1l111IlY of the prill1lllY llIYi furm llnintllTllptld radii JiOIlI lhl ((lltral l(lrc to the til llliJi11l11

ill til(gt --Hlli till (ortex (onlpri-(- till hand ot ti-slll illtlll1 lallllJilllll alld (olk It (ol1iA of a llalTllW Iilllmiddot of IlrinllllY (ortex 111(1 a broad Zlnl tlf -llolldn ry ph lilt-ill wit II p--riipgt u f i)rilllll ry

bull

bull

bull

bull

26 ECHXTCAL BlLLETIX S-I2 r s DEI)I OF ACRIClLTlltE

The original sn)1lIfieial periderm may persist fOl the life of the plaut when grown in a commercial plantation In its l111tural habitat ll(re plants toml11only become older cork eambilll11S llIay be formed gtrogns1iwly inward gradually tutting off all wstiges of primary cortex Quite oftell lIew plHllogell layers c1eelop internally in 10shy(alized ngion~ cuttinl out shell-shaped layers of primllry and periphera I s((ol1c1a ry (())-tex Such reliona I deep-eated (o~ (1e(10pshyIlHnt is quite (OIllIlIOllly tIl( result of wounding aud is therefore~ met with elm in young stelllS

ANATOMY OF HOOT

The Oot system consists chidl) of Iona medium thiek and thin Jatlrals lt1i llging at right ang-Ils from the taproot (fig ~) The roots are ypllow iII eo101 a lid the smfnceis mottled or roulhenNI by shaIlo lonuitlldinn 1 fissul(s

Cross spdiolls through slIch roots exhibit a hard pith1ps woody (He alld a broad cortex ploteclPc by a mnssie IWlidenll that is mdishyall~s(lllelltwl hy dllP ela(ks (fillG A B) The relatin thie-knlss of tllis eork la Cr is not e()JTllatld itll the diallwtlr of the root bping pr()lllin(I~lt ill thick lalerals as well as thin hl-tiarifs Onl)~ fibrous 10015 less than 15 nun in diallleltr ll(k a periderm but (lOSS(S5 a (hollSe cOelin~ of root hairs tllqrid and functional up to (lit in~(ltion point of thl rootlet Oil a lalg-lr lahral or P(11 the main r(IOt Th(se apparently lon~-persisting- root hairs liould facilshyita h the rapid absorption of watpI eyell from uperficially wctteel soils

Thl wood is (I hard the ((ntml core corresponding in size to tlw pith of the stelll bull is espteial1y cpnsl (pI 181) and frolll its l)(riphery the YllSelllal rays an sepn radiatin~ toward the COl-tCX

The lOIhx i lllassi l but lIot IHll dy ( bmad as in the stel1l (fi~ lmiddotL 11) It is made llP of (Oll(lntli( Inyels of resin callills and fibers pntbeddetl in l)lrenchymntolls ray t iSS11l

XYLE11

Sinl till elll1Wnts making up thi tiSSH( are qnite similar to those (If thl -llll1 n ddailld le5erip( ion will not Ill ginn

TIlt xI(I1 i- indi inetly ditltls(-purolls with the pores Ie nnshyI1WIOllS than in till stllll xcppt ill th( l(liull 01 thp tellt ml cme (pI h IJ) Thl middotl~el an frequently tlTallg-ed ill hort mdial rows t II at oftl1l hOI(ll on til( -a-eulnr ray l pI Ill 1) ~ el1c1oin~ blinds (l r fiber The latter form thl poundtottncl mass of the w(Jocl evell more -0 than in Ow 11(111 Ill( ((II l~r( ah-ay thiek-alled and sparsely littNl roml lHllluehyma is paratlllc1ieal and sparse

TIl nleular rays ale fartllll t1plllt and hlOlHI(r than the rays in lllt lllll )Iost of t helll nn (ry tall 0 that 1l111IlY of the prill1lllY llIYi furm llnintllTllptld radii JiOIlI lhl ((lltral l(lrc to the til llliJi11l11

ill til(gt --Hlli till (ortex (onlpri-(- till hand ot ti-slll illtlll1 lallllJilllll alld (olk It (ol1iA of a llalTllW Iilllmiddot of IlrinllllY (ortex 111(1 a broad Zlnl tlf -llolldn ry ph lilt-ill wit II p--riipgt u f i)rilllll ry

bull

bull

bull

bull

rrthnllal Bulletin S U L~~ S Department of Agnculturtmiddot PLATE 18

bull

-

-= -

-= shy shy

- - shy

shy~ 7 r I shy FCi

~ ~ til EshyIfS

~ s n

f ~ ishyS

~ Eshy

~

A EnlIIgld SP jll of XyhII1 I olel lOOt lhe large vt~(ls are allallged ill Ladial [OS Oil eirher side of the vl1fCUlaL rays enclosing a p 1IIge glollp of dplI~e lilllifI1I1 fibllS X 420 B (IOSS scetioll thlough aetie lI1el old phloPIIl 01 mediulll-sized luteml root ~Ihe ~ )lhllll grollps dplilllif(cI hy vastlIlaL rays are hroadel than those in the stem phloem (cOlllpare pI 13) the resin canals nre also tUIl- III gelltialJr it(I and thtIe is little tibeL dlClollllltnt X ]10 U

bull

bull

bull

MOHPHOLOGT AND ANATOMY OF GUAYULE 27

phloem occasionally recognizable in younger roots Since the Clllll shy

billill in the Ioots of gllayulc is hypodermal in origin and lelnttins acti n for a very long time the primary cortex persists although in alterNI fOIIII Hen in fairly old 100t5 (fig 16 1) its inner COIlshy

t01l1 is lasily delimited by following the deeply staining Caspnrian strips of the elldodermis In young roots the primRly cortpx is fairly prominent (fig 16 1) but as the root enlarges and secondary phloNI1 becomes more massive the cortical cells are stretched tanshygentiuLly anticlinal diyisions become fewer and the eelL lumen is obliteluted making it intT(asingly difficult to separate this layer 110111 adjacNlt tissues

ACTIn SECONDAHY PIlLOE~[

The groups of aei in sl(olHlalY phloem an lIot rndialLy elongated as ill tllt st(111 (fig 1-1 A) but apptar broader tangentially (fig 14 8) also the glOUP- are Ipss distinetly delimitecl from the vascular mys

The phloem is ma(l( up of sie( tubes companion cells and phloem pllcnchYllla TI( it-( tub(s 11( larger than those of the phloem in the telll alaI tlwre is a conspicuous difleleIHe between the size of tilt silmiddot( lubes Hlld companioll cells in (IOS Sletioll tPI 20 il and 11) Ph 10(111 palpn(iIyma ((1s are elongated redangular in radial s((tion and thl walls are lHIily pittll (pI 13B)

The nls(uial ray aLe continuous -ith those of the xylem They are bloatiPI t ha n thl ra s in t he stem nIllI UeCOlll een more COIIshy

pi(uolls by sp~(ad ing ollt fa nlike oon a Itel tlIPy cnler t1~e phIOlnl (pI 19 8) follll of the smaller secolldary rays end bl1l1Clly beshy(lllSl (acil Illwl) dillel(ntiat(d ring of rlsill canals has a larger nllllllwr of callaLs thall thl ollie ring In lIeh plaees two resin canah apPplI ill juxtapositioll with a sillgl( older oIll and the vasshy(iliaI ray llltwl(1l thlsl (allal aIllI till pldo(lll groups centrad to tlH1lI tlrlllillates just bliow till oicllr callal (pI In 1)

The I(in canais in the p(olldal) phiol11I of the root arc rarely spillrical bllt 011 ollpn rNillCltL to n1lIl slits in the oldel part of till (oliex TIll (allais a 11 (OIlIII10lliv sUITouIHI((l by s(elal rows of pa rCIllilYIIla (ells ltJeri ld 110111 till camhi urn though oeeasionally Illlillinal diisions ill the q)itileliulIl IIIay cOlltiibute locally tl) this jaekPt

OLD Ill LOE~[

Clssation of aetiity in the secondary phlo(1ll of the root appears to 1)( nHlI( lrfldual thall in till ittIll sinl( fiber diflprpntintion so plOll1inlnt flat II 1( of thl phloPlll of til( st(m is Illuch less l)roshy1I01111(lC 1llIl alld ill pia(ts altoglther -alltinf (fig H B)

In til( stPIll Iinls 01 I(sin canals aitllIlate with ballds of fibel~ but in til root two Illlgs of IPsin canals oftpn intpITlllt llltwlen Iing of Higtlls thOllfh fl((pH~nt iy slllall groups of seielllHilYIIIl all intll shypontld locally bc(weln rows of resin eanals (pI IH 1) Rehogresshyi( changls in thl oh1lt1 phlo(1ll tisSllP wr(tlwl a((olllllallipd by diflplpntiatinl1 of secIPI(hYlllH or not lO 011 as in the stllll Sien~ tulws nnd (olllpanioll (plls middot(oiiaps(l and their former location is inshydicated oniy by llltaill thidipl(ld IcgiOllS in the cell wall (pI 19 1)

28 TECHNICAL BULLETIN 842 U S DEPT OF AGlUCLlURE

Phloem parenchyma cells may enlurge without apparent thickening bull of their walli 01 they become seier(nchymatolls wholly 01 ill put These groups of schlelHhyma 01 tibelS have a gleatll tangentinl than radial extent Sometimes adjacent groups wi 1l coaielce in which (lise neighIJolillg ray (e1s also blcome sclerotic

Although retloglssin changes in til( phloem of the root me not so pronounced liS in thc stem and nrc lntcr to nppeul the adive life of the seconduly phloem probuhly is thegt SlInll as ill the S(III Callus pings oel the sieve plates bC(OIne evidcnt at the (ml of the growing season and with the ntlV(n~ of IWW gt)wth till old sieve tUblS bcshy(omo oblittlaed nnd ((lilaps( while the slllltlllllLling palllIlhYIl1Il cells clIiurgc alld oftell lignify

STHUCTlTHE OF TI-m PEDUNCLE

TIl( pNlllll(ll 01 main shoot or till inflmpstluee is lxc(Nlingly sip 11(1 ll and lIlay attain a IllIgih of 20 el11 Allatolllilally it is charshyadelizNI hy all lxlessi 1 IPYllo(lnl(lIt 0 r lIl(ellall iln I tissue hieh ja(kcts till Iatlwl wpakly dllloppd ystllllr bundl(s often (0111- bull

pletely In tlanSWIS( S(ction till Iwciulll1e appears fluhd with narshyrow (ollllllhymntons ridps alhrnatin with broad strips or dtloshyI(nchyma TIIP lpidlrlll is (o(li ng t h( (ollcnlhyma ritlpps is comshyposed of (Iongated poinil([ ((lis but the epidermal cells ill the depresshysion 1wbYPtlI the Iidps alp short iITlnlal alld eontaill stolllat(s T-sltaped hais typital ot tlte PlliJls((IlCC of (paf and stem clothe til( en ti Ie ollte stllface

Corte nnd pith an similar ill stlllciull til those of yotmg stems exc-ppl that ill lIlatlllC [wdllnclps solitary (orti(al (ells may become thitk-wallcd alld lilIify hilt the pith mny l)lto111c [ilIiticd ill part A IWli((11I as 1l)lolltd by Lloyd (1) has Ilut hPlll o)scled

Ihl pedullell laeks I(sill callai ill the pith bllt has t ilgular t0111shypillIHlIt of thlse in the tortex

STRUCTURE OF THE LEAF

COTYLEDON

Th( (otyhdom 11( Y(Iy small (3G ml11 gt~ 45 111m) tntile-mar- bull gilwd and oulHI (II (Inti ill olltlin( (p 2 A) The lwtiole ltas t lIli(i1ib alld two laterals which IIpOIl lntlIing the lamina hlanch pofllslIy to form a olllplieat~d ldiellillm

TIll Illsophyll is (Oll1pos(([ of six laPls of cells of which the upper two f01l1l thl ptlisadl I(i Oil Thl spongy cells ucljaeent to the ptdisadl laytmiddot lin fnqu(lItly plollated tofoJ1H a tJansition ~t(llllatls HIV fOlllld 011 both slIlfa((s their frcquPIIlY bping slightly gnatpl ill tilt IIPIWI TlllLp an 110 I(sin (anals ill the blad( and both the upper lllld Ow 10(1 epidplmis a1e ilee from hair

TIHE LEAF

The goss morphology of the tJlt lenyps alld the lliffplen(l thnt (xists bltwlln SUlllml1 nlH[ intel ilnni dlcacly huve been pointed out They are vllYmiddotaliaLlp in furlll u fcw types are illustrated in ligull 1i 1

bull

bull PLATE 20

1 EtlIlmiddotd llnIIIth Itthl phlllllIl lit 11 X TIL n (ro lllillil or It[Vl phTIlIi tlally 1llIjl1 III lto 1lllIilld 111111111lt 11( Ihl InlW il IJlIl( Hltl tl Iphlili IoIlllll (lIIprrriulI 11- gtlt lIiU ((lil 11 1t I fllL C l IUPIIiol1 lIt ~ipn flh --iYl ill pltlH~lln of -tiltI)

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

~ ~ til EshyIfS

~ s n

f ~ ishyS

~ Eshy

~

A EnlIIgld SP jll of XyhII1 I olel lOOt lhe large vt~(ls are allallged ill Ladial [OS Oil eirher side of the vl1fCUlaL rays enclosing a p 1IIge glollp of dplI~e lilllifI1I1 fibllS X 420 B (IOSS scetioll thlough aetie lI1el old phloPIIl 01 mediulll-sized luteml root ~Ihe ~ )lhllll grollps dplilllif(cI hy vastlIlaL rays are hroadel than those in the stem phloem (cOlllpare pI 13) the resin canals nre also tUIl- III gelltialJr it(I and thtIe is little tibeL dlClollllltnt X ]10 U

bull

bull

bull

MOHPHOLOGT AND ANATOMY OF GUAYULE 27

phloem occasionally recognizable in younger roots Since the Clllll shy

billill in the Ioots of gllayulc is hypodermal in origin and lelnttins acti n for a very long time the primary cortex persists although in alterNI fOIIII Hen in fairly old 100t5 (fig 16 1) its inner COIlshy

t01l1 is lasily delimited by following the deeply staining Caspnrian strips of the elldodermis In young roots the primRly cortpx is fairly prominent (fig 16 1) but as the root enlarges and secondary phloNI1 becomes more massive the cortical cells are stretched tanshygentiuLly anticlinal diyisions become fewer and the eelL lumen is obliteluted making it intT(asingly difficult to separate this layer 110111 adjacNlt tissues

ACTIn SECONDAHY PIlLOE~[

The groups of aei in sl(olHlalY phloem an lIot rndialLy elongated as ill tllt st(111 (fig 1-1 A) but apptar broader tangentially (fig 14 8) also the glOUP- are Ipss distinetly delimitecl from the vascular mys

The phloem is ma(l( up of sie( tubes companion cells and phloem pllcnchYllla TI( it-( tub(s 11( larger than those of the phloem in the telll alaI tlwre is a conspicuous difleleIHe between the size of tilt silmiddot( lubes Hlld companioll cells in (IOS Sletioll tPI 20 il and 11) Ph 10(111 palpn(iIyma ((1s are elongated redangular in radial s((tion and thl walls are lHIily pittll (pI 13B)

The nls(uial ray aLe continuous -ith those of the xylem They are bloatiPI t ha n thl ra s in t he stem nIllI UeCOlll een more COIIshy

pi(uolls by sp~(ad ing ollt fa nlike oon a Itel tlIPy cnler t1~e phIOlnl (pI 19 8) follll of the smaller secolldary rays end bl1l1Clly beshy(lllSl (acil Illwl) dillel(ntiat(d ring of rlsill canals has a larger nllllllwr of callaLs thall thl ollie ring In lIeh plaees two resin canah apPplI ill juxtapositioll with a sillgl( older oIll and the vasshy(iliaI ray llltwl(1l thlsl (allal aIllI till pldo(lll groups centrad to tlH1lI tlrlllillates just bliow till oicllr callal (pI In 1)

The I(in canais in the p(olldal) phiol11I of the root arc rarely spillrical bllt 011 ollpn rNillCltL to n1lIl slits in the oldel part of till (oliex TIll (allais a 11 (OIlIII10lliv sUITouIHI((l by s(elal rows of pa rCIllilYIIla (ells ltJeri ld 110111 till camhi urn though oeeasionally Illlillinal diisions ill the q)itileliulIl IIIay cOlltiibute locally tl) this jaekPt

OLD Ill LOE~[

Clssation of aetiity in the secondary phlo(1ll of the root appears to 1)( nHlI( lrfldual thall in till ittIll sinl( fiber diflprpntintion so plOll1inlnt flat II 1( of thl phloPlll of til( st(m is Illuch less l)roshy1I01111(lC 1llIl alld ill pia(ts altoglther -alltinf (fig H B)

In til( stPIll Iinls 01 I(sin canals aitllIlate with ballds of fibel~ but in til root two Illlgs of IPsin canals oftpn intpITlllt llltwlen Iing of Higtlls thOllfh fl((pH~nt iy slllall groups of seielllHilYIIIl all intll shypontld locally bc(weln rows of resin eanals (pI IH 1) Rehogresshyi( changls in thl oh1lt1 phlo(1ll tisSllP wr(tlwl a((olllllallipd by diflplpntiatinl1 of secIPI(hYlllH or not lO 011 as in the stllll Sien~ tulws nnd (olllpanioll (plls middot(oiiaps(l and their former location is inshydicated oniy by llltaill thidipl(ld IcgiOllS in the cell wall (pI 19 1)

28 TECHNICAL BULLETIN 842 U S DEPT OF AGlUCLlURE

Phloem parenchyma cells may enlurge without apparent thickening bull of their walli 01 they become seier(nchymatolls wholly 01 ill put These groups of schlelHhyma 01 tibelS have a gleatll tangentinl than radial extent Sometimes adjacent groups wi 1l coaielce in which (lise neighIJolillg ray (e1s also blcome sclerotic

Although retloglssin changes in til( phloem of the root me not so pronounced liS in thc stem and nrc lntcr to nppeul the adive life of the seconduly phloem probuhly is thegt SlInll as ill the S(III Callus pings oel the sieve plates bC(OIne evidcnt at the (ml of the growing season and with the ntlV(n~ of IWW gt)wth till old sieve tUblS bcshy(omo oblittlaed nnd ((lilaps( while the slllltlllllLling palllIlhYIl1Il cells clIiurgc alld oftell lignify

STHUCTlTHE OF TI-m PEDUNCLE

TIl( pNlllll(ll 01 main shoot or till inflmpstluee is lxc(Nlingly sip 11(1 ll and lIlay attain a IllIgih of 20 el11 Allatolllilally it is charshyadelizNI hy all lxlessi 1 IPYllo(lnl(lIt 0 r lIl(ellall iln I tissue hieh ja(kcts till Iatlwl wpakly dllloppd ystllllr bundl(s often (0111- bull

pletely In tlanSWIS( S(ction till Iwciulll1e appears fluhd with narshyrow (ollllllhymntons ridps alhrnatin with broad strips or dtloshyI(nchyma TIIP lpidlrlll is (o(li ng t h( (ollcnlhyma ritlpps is comshyposed of (Iongated poinil([ ((lis but the epidermal cells ill the depresshysion 1wbYPtlI the Iidps alp short iITlnlal alld eontaill stolllat(s T-sltaped hais typital ot tlte PlliJls((IlCC of (paf and stem clothe til( en ti Ie ollte stllface

Corte nnd pith an similar ill stlllciull til those of yotmg stems exc-ppl that ill lIlatlllC [wdllnclps solitary (orti(al (ells may become thitk-wallcd alld lilIify hilt the pith mny l)lto111c [ilIiticd ill part A IWli((11I as 1l)lolltd by Lloyd (1) has Ilut hPlll o)scled

Ihl pedullell laeks I(sill callai ill the pith bllt has t ilgular t0111shypillIHlIt of thlse in the tortex

STRUCTURE OF THE LEAF

COTYLEDON

Th( (otyhdom 11( Y(Iy small (3G ml11 gt~ 45 111m) tntile-mar- bull gilwd and oulHI (II (Inti ill olltlin( (p 2 A) The lwtiole ltas t lIli(i1ib alld two laterals which IIpOIl lntlIing the lamina hlanch pofllslIy to form a olllplieat~d ldiellillm

TIll Illsophyll is (Oll1pos(([ of six laPls of cells of which the upper two f01l1l thl ptlisadl I(i Oil Thl spongy cells ucljaeent to the ptdisadl laytmiddot lin fnqu(lItly plollated tofoJ1H a tJansition ~t(llllatls HIV fOlllld 011 both slIlfa((s their frcquPIIlY bping slightly gnatpl ill tilt IIPIWI TlllLp an 110 I(sin (anals ill the blad( and both the upper lllld Ow 10(1 epidplmis a1e ilee from hair

TIHE LEAF

The goss morphology of the tJlt lenyps alld the lliffplen(l thnt (xists bltwlln SUlllml1 nlH[ intel ilnni dlcacly huve been pointed out They are vllYmiddotaliaLlp in furlll u fcw types are illustrated in ligull 1i 1

bull

bull PLATE 20

1 EtlIlmiddotd llnIIIth Itthl phlllllIl lit 11 X TIL n (ro lllillil or It[Vl phTIlIi tlally 1llIjl1 III lto 1lllIilld 111111111lt 11( Ihl InlW il IJlIl( Hltl tl Iphlili IoIlllll (lIIprrriulI 11- gtlt lIiU ((lil 11 1t I fllL C l IUPIIiol1 lIt ~ipn flh --iYl ill pltlH~lln of -tiltI)

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

bull

bull

bull

MOHPHOLOGT AND ANATOMY OF GUAYULE 27

phloem occasionally recognizable in younger roots Since the Clllll shy

billill in the Ioots of gllayulc is hypodermal in origin and lelnttins acti n for a very long time the primary cortex persists although in alterNI fOIIII Hen in fairly old 100t5 (fig 16 1) its inner COIlshy

t01l1 is lasily delimited by following the deeply staining Caspnrian strips of the elldodermis In young roots the primRly cortpx is fairly prominent (fig 16 1) but as the root enlarges and secondary phloNI1 becomes more massive the cortical cells are stretched tanshygentiuLly anticlinal diyisions become fewer and the eelL lumen is obliteluted making it intT(asingly difficult to separate this layer 110111 adjacNlt tissues

ACTIn SECONDAHY PIlLOE~[

The groups of aei in sl(olHlalY phloem an lIot rndialLy elongated as ill tllt st(111 (fig 1-1 A) but apptar broader tangentially (fig 14 8) also the glOUP- are Ipss distinetly delimitecl from the vascular mys

The phloem is ma(l( up of sie( tubes companion cells and phloem pllcnchYllla TI( it-( tub(s 11( larger than those of the phloem in the telll alaI tlwre is a conspicuous difleleIHe between the size of tilt silmiddot( lubes Hlld companioll cells in (IOS Sletioll tPI 20 il and 11) Ph 10(111 palpn(iIyma ((1s are elongated redangular in radial s((tion and thl walls are lHIily pittll (pI 13B)

The nls(uial ray aLe continuous -ith those of the xylem They are bloatiPI t ha n thl ra s in t he stem nIllI UeCOlll een more COIIshy

pi(uolls by sp~(ad ing ollt fa nlike oon a Itel tlIPy cnler t1~e phIOlnl (pI 19 8) follll of the smaller secolldary rays end bl1l1Clly beshy(lllSl (acil Illwl) dillel(ntiat(d ring of rlsill canals has a larger nllllllwr of callaLs thall thl ollie ring In lIeh plaees two resin canah apPplI ill juxtapositioll with a sillgl( older oIll and the vasshy(iliaI ray llltwl(1l thlsl (allal aIllI till pldo(lll groups centrad to tlH1lI tlrlllillates just bliow till oicllr callal (pI In 1)

The I(in canais in the p(olldal) phiol11I of the root arc rarely spillrical bllt 011 ollpn rNillCltL to n1lIl slits in the oldel part of till (oliex TIll (allais a 11 (OIlIII10lliv sUITouIHI((l by s(elal rows of pa rCIllilYIIla (ells ltJeri ld 110111 till camhi urn though oeeasionally Illlillinal diisions ill the q)itileliulIl IIIay cOlltiibute locally tl) this jaekPt

OLD Ill LOE~[

Clssation of aetiity in the secondary phlo(1ll of the root appears to 1)( nHlI( lrfldual thall in till ittIll sinl( fiber diflprpntintion so plOll1inlnt flat II 1( of thl phloPlll of til( st(m is Illuch less l)roshy1I01111(lC 1llIl alld ill pia(ts altoglther -alltinf (fig H B)

In til( stPIll Iinls 01 I(sin canals aitllIlate with ballds of fibel~ but in til root two Illlgs of IPsin canals oftpn intpITlllt llltwlen Iing of Higtlls thOllfh fl((pH~nt iy slllall groups of seielllHilYIIIl all intll shypontld locally bc(weln rows of resin eanals (pI IH 1) Rehogresshyi( changls in thl oh1lt1 phlo(1ll tisSllP wr(tlwl a((olllllallipd by diflplpntiatinl1 of secIPI(hYlllH or not lO 011 as in the stllll Sien~ tulws nnd (olllpanioll (plls middot(oiiaps(l and their former location is inshydicated oniy by llltaill thidipl(ld IcgiOllS in the cell wall (pI 19 1)

28 TECHNICAL BULLETIN 842 U S DEPT OF AGlUCLlURE

Phloem parenchyma cells may enlurge without apparent thickening bull of their walli 01 they become seier(nchymatolls wholly 01 ill put These groups of schlelHhyma 01 tibelS have a gleatll tangentinl than radial extent Sometimes adjacent groups wi 1l coaielce in which (lise neighIJolillg ray (e1s also blcome sclerotic

Although retloglssin changes in til( phloem of the root me not so pronounced liS in thc stem and nrc lntcr to nppeul the adive life of the seconduly phloem probuhly is thegt SlInll as ill the S(III Callus pings oel the sieve plates bC(OIne evidcnt at the (ml of the growing season and with the ntlV(n~ of IWW gt)wth till old sieve tUblS bcshy(omo oblittlaed nnd ((lilaps( while the slllltlllllLling palllIlhYIl1Il cells clIiurgc alld oftell lignify

STHUCTlTHE OF TI-m PEDUNCLE

TIl( pNlllll(ll 01 main shoot or till inflmpstluee is lxc(Nlingly sip 11(1 ll and lIlay attain a IllIgih of 20 el11 Allatolllilally it is charshyadelizNI hy all lxlessi 1 IPYllo(lnl(lIt 0 r lIl(ellall iln I tissue hieh ja(kcts till Iatlwl wpakly dllloppd ystllllr bundl(s often (0111- bull

pletely In tlanSWIS( S(ction till Iwciulll1e appears fluhd with narshyrow (ollllllhymntons ridps alhrnatin with broad strips or dtloshyI(nchyma TIIP lpidlrlll is (o(li ng t h( (ollcnlhyma ritlpps is comshyposed of (Iongated poinil([ ((lis but the epidermal cells ill the depresshysion 1wbYPtlI the Iidps alp short iITlnlal alld eontaill stolllat(s T-sltaped hais typital ot tlte PlliJls((IlCC of (paf and stem clothe til( en ti Ie ollte stllface

Corte nnd pith an similar ill stlllciull til those of yotmg stems exc-ppl that ill lIlatlllC [wdllnclps solitary (orti(al (ells may become thitk-wallcd alld lilIify hilt the pith mny l)lto111c [ilIiticd ill part A IWli((11I as 1l)lolltd by Lloyd (1) has Ilut hPlll o)scled

Ihl pedullell laeks I(sill callai ill the pith bllt has t ilgular t0111shypillIHlIt of thlse in the tortex

STRUCTURE OF THE LEAF

COTYLEDON

Th( (otyhdom 11( Y(Iy small (3G ml11 gt~ 45 111m) tntile-mar- bull gilwd and oulHI (II (Inti ill olltlin( (p 2 A) The lwtiole ltas t lIli(i1ib alld two laterals which IIpOIl lntlIing the lamina hlanch pofllslIy to form a olllplieat~d ldiellillm

TIll Illsophyll is (Oll1pos(([ of six laPls of cells of which the upper two f01l1l thl ptlisadl I(i Oil Thl spongy cells ucljaeent to the ptdisadl laytmiddot lin fnqu(lItly plollated tofoJ1H a tJansition ~t(llllatls HIV fOlllld 011 both slIlfa((s their frcquPIIlY bping slightly gnatpl ill tilt IIPIWI TlllLp an 110 I(sin (anals ill the blad( and both the upper lllld Ow 10(1 epidplmis a1e ilee from hair

TIHE LEAF

The goss morphology of the tJlt lenyps alld the lliffplen(l thnt (xists bltwlln SUlllml1 nlH[ intel ilnni dlcacly huve been pointed out They are vllYmiddotaliaLlp in furlll u fcw types are illustrated in ligull 1i 1

bull

bull PLATE 20

1 EtlIlmiddotd llnIIIth Itthl phlllllIl lit 11 X TIL n (ro lllillil or It[Vl phTIlIi tlally 1llIjl1 III lto 1lllIilld 111111111lt 11( Ihl InlW il IJlIl( Hltl tl Iphlili IoIlllll (lIIprrriulI 11- gtlt lIiU ((lil 11 1t I fllL C l IUPIIiol1 lIt ~ipn flh --iYl ill pltlH~lln of -tiltI)

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

28 TECHNICAL BULLETIN 842 U S DEPT OF AGlUCLlURE

Phloem parenchyma cells may enlurge without apparent thickening bull of their walli 01 they become seier(nchymatolls wholly 01 ill put These groups of schlelHhyma 01 tibelS have a gleatll tangentinl than radial extent Sometimes adjacent groups wi 1l coaielce in which (lise neighIJolillg ray (e1s also blcome sclerotic

Although retloglssin changes in til( phloem of the root me not so pronounced liS in thc stem and nrc lntcr to nppeul the adive life of the seconduly phloem probuhly is thegt SlInll as ill the S(III Callus pings oel the sieve plates bC(OIne evidcnt at the (ml of the growing season and with the ntlV(n~ of IWW gt)wth till old sieve tUblS bcshy(omo oblittlaed nnd ((lilaps( while the slllltlllllLling palllIlhYIl1Il cells clIiurgc alld oftell lignify

STHUCTlTHE OF TI-m PEDUNCLE

TIl( pNlllll(ll 01 main shoot or till inflmpstluee is lxc(Nlingly sip 11(1 ll and lIlay attain a IllIgih of 20 el11 Allatolllilally it is charshyadelizNI hy all lxlessi 1 IPYllo(lnl(lIt 0 r lIl(ellall iln I tissue hieh ja(kcts till Iatlwl wpakly dllloppd ystllllr bundl(s often (0111- bull

pletely In tlanSWIS( S(ction till Iwciulll1e appears fluhd with narshyrow (ollllllhymntons ridps alhrnatin with broad strips or dtloshyI(nchyma TIIP lpidlrlll is (o(li ng t h( (ollcnlhyma ritlpps is comshyposed of (Iongated poinil([ ((lis but the epidermal cells ill the depresshysion 1wbYPtlI the Iidps alp short iITlnlal alld eontaill stolllat(s T-sltaped hais typital ot tlte PlliJls((IlCC of (paf and stem clothe til( en ti Ie ollte stllface

Corte nnd pith an similar ill stlllciull til those of yotmg stems exc-ppl that ill lIlatlllC [wdllnclps solitary (orti(al (ells may become thitk-wallcd alld lilIify hilt the pith mny l)lto111c [ilIiticd ill part A IWli((11I as 1l)lolltd by Lloyd (1) has Ilut hPlll o)scled

Ihl pedullell laeks I(sill callai ill the pith bllt has t ilgular t0111shypillIHlIt of thlse in the tortex

STRUCTURE OF THE LEAF

COTYLEDON

Th( (otyhdom 11( Y(Iy small (3G ml11 gt~ 45 111m) tntile-mar- bull gilwd and oulHI (II (Inti ill olltlin( (p 2 A) The lwtiole ltas t lIli(i1ib alld two laterals which IIpOIl lntlIing the lamina hlanch pofllslIy to form a olllplieat~d ldiellillm

TIll Illsophyll is (Oll1pos(([ of six laPls of cells of which the upper two f01l1l thl ptlisadl I(i Oil Thl spongy cells ucljaeent to the ptdisadl laytmiddot lin fnqu(lItly plollated tofoJ1H a tJansition ~t(llllatls HIV fOlllld 011 both slIlfa((s their frcquPIIlY bping slightly gnatpl ill tilt IIPIWI TlllLp an 110 I(sin (anals ill the blad( and both the upper lllld Ow 10(1 epidplmis a1e ilee from hair

TIHE LEAF

The goss morphology of the tJlt lenyps alld the lliffplen(l thnt (xists bltwlln SUlllml1 nlH[ intel ilnni dlcacly huve been pointed out They are vllYmiddotaliaLlp in furlll u fcw types are illustrated in ligull 1i 1

bull

bull PLATE 20

1 EtlIlmiddotd llnIIIth Itthl phlllllIl lit 11 X TIL n (ro lllillil or It[Vl phTIlIi tlally 1llIjl1 III lto 1lllIilld 111111111lt 11( Ihl InlW il IJlIl( Hltl tl Iphlili IoIlllll (lIIprrriulI 11- gtlt lIiU ((lil 11 1t I fllL C l IUPIIiol1 lIt ~ipn flh --iYl ill pltlH~lln of -tiltI)

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

bull PLATE 20

1 EtlIlmiddotd llnIIIth Itthl phlllllIl lit 11 X TIL n (ro lllillil or It[Vl phTIlIi tlally 1llIjl1 III lto 1lllIilld 111111111lt 11( Ihl InlW il IJlIl( Hltl tl Iphlili IoIlllll (lIIprrriulI 11- gtlt lIiU ((lil 11 1t I fllL C l IUPIIiol1 lIt ~ipn flh --iYl ill pltlH~lln of -tiltI)

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

Technilllullelin a2ll s Dcputmenl pf A~ri(lIlture PLATE 21

bull

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

Technical Bulletin 842 U S Department of Agriculture PLATE 22

Semiciingmllllllntic drnwing of cross section of ba8e of actively growing 4-monthshyold hoot X 175 Orange color indicates rubber blue color starch

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

29 ~vIORPHOLOGY AND AJATOMY OF GUAYULE

FIGlm~ IT-A Ynialillil ill IYllli of 11111111(1 Ilan H el 1(Cii(1I lIf midrib of Ita with dpl aud PIlIIalIPin (a 111 I X o

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

30 1EClL~ICL BlLLETlX S12~ 1 S DEPT Ol~ AGRICULlUHE

Exc(ptin the region of till midrib tl1( lamina is thin (fig 18 4) The epldellnal (ells in surfac( iew are Ny sinuons (fig 18 0) stomates an faidy abundant and O(CUI with auout eqllal fllquency on both slIlfac(s The stonwhs are of the comlllOIl type somewhat depress((l bllow the 1(l1 of the (pidllmis the walls of the gilaId (plls slighty thkkpllP(l ill thl Ilgion of the stomatal cavity 1he

FIGn~ 1-1 (Inlt ((Iion of I(lf II IlIlnlgptl Jlrtmiddot ()f (rns 1(lion tn how (Itta it ill 1111(IUI( X WU c ulfl(p itw (f UPl1 fpi(prmi X OO D TYIlCS (If hair X OO

n1lsophyll llltlsist altno~t lntinly of pali-adf (PU (qual in shnp( and di-trihutioll Oil both ~lIda(( (fit l~ B) Hein (anals 1(

found on both ides TlHn tin 10 Il) 12 (Jnals on th( Y(lltml or UPP(L sille and 4- to )011 the dOl-al or 10(1 TIll dor-l (anals a(TOmpany till Itaf-tm(( Illtlldl(s Imt tIll (Iltral (anal originate dl n()o ill tll( IlPtiol( Iwlt tlHY f()lIow till principal lins and give oft -idl IJllIldH~ a till llltlL till lJ1~alllgi[)ll of tile lamina

lfORPI-IOLOGY AXD ANATOMY OF GUAYULE 31

There are two types of hairs found on eithel leaf surface The l1Hh(gt cOlllmon type is the large asymmetrical T-shaped hail (fig 18 D) with It unicelllliu or bicellular stnlk which is so short thnt the hail appeals sessile Lloyd (4) describes and illustrates only T -slullWd hails with to- and (yen three-cdled stalks yet the oneshycelled stalk is YeLy common Much Jess fleqllently found is a small multicellulaL hail the ultimate cell of which is long and slender

OlUCIN AND STORACE OF RUBBER

Ill( OC(IIIII)(I of IIlbl)(t andits clnhIs of distriblltion in thl Yalions plant organs havl been deselibld in detail by Hoss (6) and Lloyd (4) Hllbber is found in all plant organs Imt only the stem and the root han sldlieilnt qllantities to bl of economie illtelest

O(IHllIlIy Slllakillg ill plants of ha1l8t size the vascnlar rays of the phl()(111 and to n lessl1 extent those of the xylem contain by far the largest al1lount of rubbel (pI 21 A B) Smaller quantities are found ill jaekding cells of the resin cana and rathet insignificant quanti tilS in pith primary coLtex amI xylem parenchyma The actin si(I-tllbe tiSgttll contains practically no rubbCl The latter thollgh pelhaps of SOllle dlbatable signilielllce in the economy of the plant would IUle 110 yalue as stored rllbblL since the active phloem )llomes in part obliterated and in part displaced by sc1erenchymatous tismc

In yOllng plants in which the prillUlry tissuls 1111 till a eonspicuous part of the anatomical pictl1re most rubber is found in the pLimary lortex pith and YaS(lllal rays as well us ill the parenchymatous jacket of t ht primal l(sin canal

In yOllllg~ actin I) ~rowing stlms lubbll applills first in the epitheshylial c(ll of the plilllll) cOltieal and pith callaIs bllt it is much more (onSpilllOllS in the sl(Ilting laYN of the nlly formed s((01Hlary resin callais ~mal glanllies are also obsllI~d in thl eells of the primary cortlX pith and tIll inllPI (plls (If thl rays (pI 22) Of intNest is the (listlibllt ion of starch which is limitld to tIll endodellllis and the layer of pallllchrlll1l (plls slllathing thl H(lltin layer of the Ilsin canals l pI 2) ~omlt imls sla Ich is a Iso ohsern~d in some of the parenchyma lllls illllllld ia t(I~ i IIsidl lhe endoderlll is between the groups of scl(J(lldlllla lilJPls

Ill old roots and stpms thnt Hle (omposecl mostly of secondHIY tisslllS IlIbhll sellllion is rllate(l 10 the agl of the cells as formed by the lambilllll SineI llIbbll normally appears first in older cells ex(ept for till epithelium of thp IPsill (allnls thl direction of rubber npplHlalH1 ill be for till pit I0(111 llnlrad and for Iltl Yas(ulal rays of the wood (Plltrifllgal lor thl ~alllc reason cells closcr to the fruing poi lIt of tl(planl axis will contain lcss rubber than will HlOI( ha~aL lllk

TIll tinll faetor for 11Ih1JPl syntllsi~ and the duration of the rest Jltriot for ntlXinltllll lubbt1 ~tltjragl will not be taken up in this bulshyletin _econling to Lloyd l~middot)-thl time nt hi(h til( maximl1JlJ 1111(1111 of rl1hhlr JlJily he eXIJtctld tlitlers with lhl Illth (If rill Iluwilll ~(I()II witi(h IhllllHl 1I1~1ll tilt raill(all alld the illtPlliry lIf till (Inl1lln ftllloilll thp lIH1xillllllll ql1nntil~ is ((rtaillly Jlot llalhl(1 in (I1I1t 1I101I1h ant Illwth eOlllllleIlC~ lnd it i highly 11olmule thnt six ur mure lllUlllhs lllUt elap~e

32 TECH~ICAL BCLLETIN 842 U S DEPT OF AGRICULlURE

ANATOMICAL STRUCTURE IN RELATION TO RUBBER CONTENT AND TYPE

The rute of growth determines the total increment of xylem and phloem According to Lloyd en 1110re phloem is produced by dlYshyland plants than by plants under irrigation but the sum total of lubber-storing tissue IlloLluced under inigatioll is nevertheless greater since the total glowth inClenwnt is larger

The efled ofirtigation 011 structure also may find expression in the detttilecl anatomical pictnre of the nod itself The xylem of ilTigated plants accorcling to Lloyd is hal(lel the vessels are smaller and the lIlechnlli(al element are mOre compnet The VtlSCUIal rays also are smaller thtir c~ls thick-walled and ligllifi~d Lloyd undoubtedly observed these dlfrerences but nnless observatIOns tire made with C0111shy

palllthe material one lunjr not gelleralize too freely Valj(ties differ These llifferences mny b( qllalitatiY(~ tiS well as quantitative (pI 23 A to F) The r(latiYe size of eOl((X tllltl wood appear to be a varietal characteristic that may Hot l)(gt affected by eln-ironment although the total growth inCrcn1(Ilt would Le in clircct relation to the amount of available water Veampel size ns seen in CIOSS section also is apt to be a varietal characteristic and not an expression of available yater In one instance (pI 23 E~ F) the largN-size wssel ere Ielated to high lnbb(r cont(llt perhaps an ncci(hnttilol(lation but in this case not a reponse of rate of growth to differ(nces in yater supply

Very old plallts mHy sho lignifieation in the older part of the rays but in plants of economic illtlrest (t to 5 years old) nune of the matelllli stuclietl showed either jllCrlaSe in thickness of the ray cells 01 their 1ilnifkation SolitalY O groups of pith cells lin o(easionally become thick-walled and iglliti(d n fad of rather minor importance

As already stated in tlll introduction it is necesstuy to knoW the varieties anatomically befoll nttempting to intclpl(t the eflect of environment on strllctnr( 8inc( lubber storage appears to be related to stlUctllre vari(tits with a grlntll storage space for ruuber would furnish b(tter Ill material for seledive breeding ork than would Ytrieti(s ill whieh the sl(ondary cortex igt thin eYen though both Tarieties might test high in jwrctntnge of rubber The lelatiye gloyth inClenKllts ()f xylem llllll phloem ml~)r alo cliffet with differel1t yarieshyties Only sel(ctionsin whieh phloem dlYelopment is favored oyer xylpl11 slwulcl be afforcled a future in a bl(eding program Nothing is known about th( grand pNiod of cambium aetiyity in the spring although such n knowledge would hae a defil1lte influenee on the dute for the withholding ofillil1atiol1 Y(ltel to stimulate the synthesis of rubber Again in 10culitieswith n long groYing season definite data on the length of the r(sl period for maximum rubber synthesis would permit n second period of active growth before cell division is susshypended with the advent of winter

The anatomical approach in an imploYement progrnm for guayule has much to r((()mllll~llditse1f it affords a scientific basis for purshyposeful seleetion and points to short cuts in the attainment of this goal

bull

bull

bull

bull

bull

l (II q11 hllIll~h phlplllI 11lt1 IIIiphtI11 xI1I1I1 11 -gt1lilll l11ill Xn Hili Ili in 1111gt1gt01 2 Iild (IIIX 1111 1111 I lilll- 1111d 1 1111111 hllIJd hal d liC ldin~ pltl(lI1l1~ n tllinn~ --llnill ~o -JP lli~11 ill 11IillilI It t 11 I Iil ill 111 ILlI ilritnitti Ih IIIIl 1tlI llId ill Iuil- 1112

(Illfald ilh 1 IIII PIIlX i IlllITI 1I1l1 111 ImiddotIImiddotlllll~IllIItlUl~ l hmiddot hlaL Th Z (Ie ImiddottilI ]1111111111 b 11lt11 lhlll ill1 X~111I1 ll~

33 MORPHOLOGY AD A~ATOMY OF GUAYULE

LITERATURE CITED (1) DANOEARD P A

1881) mCHEBCHES SUR U MOllE UUNION DE LA TrOE 1cT DE TA BAOINE CJn LES DlCOTYLEDONES Botaniste1 75-12fgt

(2) DLNOVA V J SOSNOVElZ A A and SnsHIN N A 1934 CO~LPItATIVE CYTOEMDUYOIOltllCAL ANALYSlS OF TH~ VARUTlES OF

PAITHtNll~[ AllGtNTATU~1 ORAY AND PARTHENIUM INCANUM ORAY JOllr Bot de lUUSSll)(5) 447-466

(3) KOKItA E 1011 lIOllP II 0 LOGY AND Dtnxop~[tNT OF THE INLOR~SCIcNms OF IARTHENIID[

lWENTATU~( O (GUAYULEJ ANIgt OF PAHTHENIU~[ HYSTEHOIHORtS L

~losko Ohsheh ISII Prirody Otd BioI Billl (Soc Nat de MlISCOII Sect BioI Bul [1031]) pp 207-236 375-383

(4) LLOYD F E lUll GUAY1LE (IAITH~olU~( IGtNIATUM GlUYJ A RUDH~R PLNT OF THE

CHIIIUln mstUr Carncgie Illst ash PlIll 13U 213 PlImiddot iIlus

(ti) Ross H 1008 DtU ANATO~US(Ht HAU IgtEU lIEXlIuNISClIEN KAtTSCHUKPFLANZ~

OUAUlE PHTHtNllr~1 AltGtNTATU~[ GR Deut Bot Gesell I(r 26a 241-261 illus

(U) SnElt~ 13 lOHI Ttll lILNSITLON FltO~[ ROOT TO STt~1 IN IItllANTHUS ANNUlS L AND

R(Tll1I1 ~(lNrS lJlmNH AII1r )[icl1alld Nat 12 425-187 (7) YnrlE1IllN 1

188middot1 Tim IgtES eOHIOSEES 258 Pl Paris

ar( omewhat fartlJ(l apart C Rnlina train ~o 40G high in rublwT X 28 Slt out ill 1l35 alld nCI irrigntcd _-l and ( are very similar in allllcaranct middot(heing the ~aIllC tmin) aHI irrigation docs not seem to have hnd all~- (tr((( on the structurc D Salinas strain No lV low in rullllel Set out in 1930 and nCCl irrigat(ll X 28 Thc cortex is narrow and the vailnhll storage spacc for ruhber is not a glent as in l and C llut just as grcat as ill B The lliffprCllce lletwetll Band J) SllJllS to lie ihe relatively narrow band of nctive phloem in D as compared with the broad lland in

B E Enlargl(l vipw of xylen and vascular rays of strain No 406 (not irrimiddot gatcd) X ISO P Enlarged yi(w of xylem of strain 49 X 180 Note the larger vessel alld wider rays ill strain No J06 compared with those of strain No -O

ORGANIZATION OF TilE UNITED STATES DEPARTMENT OF AGRICULTURE WHEN THIS PUBLICATION WAS EITIIER FIRST PRINTED OR LAST REVISED

Secretarll of Agmiddoticlllfllre___________ _______ bull _____ bull __ Ullder Secreta 10________ _____ _ ___________ _ Assialt Seclet(lmiddot______ __ bullbull ______ bull _________ _

Director of AUIicIIlflll(I1 ntlI UelIIiOIls _______ bull ___ bull ___ _ Diredol of Fill(III(( _______ _________ _ Director of lerYolllleL_______ ___ bull __ bull____ _ bullbull __ _ DirectOl of lIfoIH1fioll _________________

Directo of El~tellsion Wor ____ bull __ _

Director of Forcign AurilIII1II1al RclllliollS_ -Solicitor______________________________ _ __ _ bull

Librarian ______________________________ _

Chief BIIIC(ll of AIri(-lIl1l1lul E(middotollolllics_______ bull_____ _

Chief Office of Cililian Con~CIt(llion Corps Aclieilies__ CIr ief Office of Ila lit a IlIl OJel( iOIlL ____ _ Atlmillist(ol of AgliclIltlll(I Re~etll(h_____ __ _ Direeo of Foo(l Prodllclion ldlll ill istmlioll _ __ Direcol of Pood Di~rilJlIiollbullldlllillisr(liol __ Plcsidcllt Commodity Creelit Corpoatioll ____________ _ Chief Forcyt Scrri((____________ bull __________________ _

Admillistratol Rlral Rc(rifictlion ~ldilliqr(iOIl

(LAum R WICKAIIil

PAUl II AImiddotPL~JlY GROER B HnL A~I UEL B BumsOl- W A JulP

~e Hoy REm lIous~ SA 1ISJlUlIY

M L WILSON

L A VHE~UR UOBEltT II SnmlJls HAIPn It SHAW 1I0WIII) R ToIUY

FREIl MORRELfbullbull

AUTHUlI B T HATCH lill

K C AlrnT~II M CUFFORIl lOWNS~NIgt

ItOY F IIENllItlCKON

J B HUTSON

LYII~ ( middotATTS

IIRRY LATnRY

This bulletin is a contri)ution froIll

lt1UliCIIII1([ RC~car(middoth ~l(IIillistl(ioll ________ I C AlCHnn lrlll1illi~t(tol

BIrcal of Plallt 111(1118111________________ ____ n ~I SALTER Cllict

Rllbbcl Plant csiUfltiolllJ_____________ 1 BUANDES Chief

Fur ~nle ii ih(l ~tlIHImiddotilllHlpllt of IhwlIlIIPlltS r ~~ (~()(rIIIl1(lIt Irililill IHlit(I 1 n-hiWl()Il U C - lli(l~ 1 ((IH

t

32 TECH~ICAL BCLLETIN 842 U S DEPT OF AGRICULlURE

ANATOMICAL STRUCTURE IN RELATION TO RUBBER CONTENT AND TYPE

The rute of growth determines the total increment of xylem and phloem According to Lloyd en 1110re phloem is produced by dlYshyland plants than by plants under irrigation but the sum total of lubber-storing tissue IlloLluced under inigatioll is nevertheless greater since the total glowth inClenwnt is larger

The efled ofirtigation 011 structure also may find expression in the detttilecl anatomical pictnre of the nod itself The xylem of ilTigated plants accorcling to Lloyd is hal(lel the vessels are smaller and the lIlechnlli(al element are mOre compnet The VtlSCUIal rays also are smaller thtir c~ls thick-walled and ligllifi~d Lloyd undoubtedly observed these dlfrerences but nnless observatIOns tire made with C0111shy

palllthe material one lunjr not gelleralize too freely Valj(ties differ These llifferences mny b( qllalitatiY(~ tiS well as quantitative (pI 23 A to F) The r(latiYe size of eOl((X tllltl wood appear to be a varietal characteristic that may Hot l)(gt affected by eln-ironment although the total growth inCrcn1(Ilt would Le in clircct relation to the amount of available water Veampel size ns seen in CIOSS section also is apt to be a varietal characteristic and not an expression of available yater In one instance (pI 23 E~ F) the largN-size wssel ere Ielated to high lnbb(r cont(llt perhaps an ncci(hnttilol(lation but in this case not a reponse of rate of growth to differ(nces in yater supply

Very old plallts mHy sho lignifieation in the older part of the rays but in plants of economic illtlrest (t to 5 years old) nune of the matelllli stuclietl showed either jllCrlaSe in thickness of the ray cells 01 their 1ilnifkation SolitalY O groups of pith cells lin o(easionally become thick-walled and iglliti(d n fad of rather minor importance

As already stated in tlll introduction it is necesstuy to knoW the varieties anatomically befoll nttempting to intclpl(t the eflect of environment on strllctnr( 8inc( lubber storage appears to be related to stlUctllre vari(tits with a grlntll storage space for ruuber would furnish b(tter Ill material for seledive breeding ork than would Ytrieti(s ill whieh the sl(ondary cortex igt thin eYen though both Tarieties might test high in jwrctntnge of rubber The lelatiye gloyth inClenKllts ()f xylem llllll phloem ml~)r alo cliffet with differel1t yarieshyties Only sel(ctionsin whieh phloem dlYelopment is favored oyer xylpl11 slwulcl be afforcled a future in a bl(eding program Nothing is known about th( grand pNiod of cambium aetiyity in the spring although such n knowledge would hae a defil1lte influenee on the dute for the withholding ofillil1atiol1 Y(ltel to stimulate the synthesis of rubber Again in 10culitieswith n long groYing season definite data on the length of the r(sl period for maximum rubber synthesis would permit n second period of active growth before cell division is susshypended with the advent of winter

The anatomical approach in an imploYement progrnm for guayule has much to r((()mllll~llditse1f it affords a scientific basis for purshyposeful seleetion and points to short cuts in the attainment of this goal

bull

bull

bull

bull

bull

l (II q11 hllIll~h phlplllI 11lt1 IIIiphtI11 xI1I1I1 11 -gt1lilll l11ill Xn Hili Ili in 1111gt1gt01 2 Iild (IIIX 1111 1111 I lilll- 1111d 1 1111111 hllIJd hal d liC ldin~ pltl(lI1l1~ n tllinn~ --llnill ~o -JP lli~11 ill 11IillilI It t 11 I Iil ill 111 ILlI ilritnitti Ih IIIIl 1tlI llId ill Iuil- 1112

(Illfald ilh 1 IIII PIIlX i IlllITI 1I1l1 111 ImiddotIImiddotlllll~IllIItlUl~ l hmiddot hlaL Th Z (Ie ImiddottilI ]1111111111 b 11lt11 lhlll ill1 X~111I1 ll~

33 MORPHOLOGY AD A~ATOMY OF GUAYULE

LITERATURE CITED (1) DANOEARD P A

1881) mCHEBCHES SUR U MOllE UUNION DE LA TrOE 1cT DE TA BAOINE CJn LES DlCOTYLEDONES Botaniste1 75-12fgt

(2) DLNOVA V J SOSNOVElZ A A and SnsHIN N A 1934 CO~LPItATIVE CYTOEMDUYOIOltllCAL ANALYSlS OF TH~ VARUTlES OF

PAITHtNll~[ AllGtNTATU~1 ORAY AND PARTHENIUM INCANUM ORAY JOllr Bot de lUUSSll)(5) 447-466

(3) KOKItA E 1011 lIOllP II 0 LOGY AND Dtnxop~[tNT OF THE INLOR~SCIcNms OF IARTHENIID[

lWENTATU~( O (GUAYULEJ ANIgt OF PAHTHENIU~[ HYSTEHOIHORtS L

~losko Ohsheh ISII Prirody Otd BioI Billl (Soc Nat de MlISCOII Sect BioI Bul [1031]) pp 207-236 375-383

(4) LLOYD F E lUll GUAY1LE (IAITH~olU~( IGtNIATUM GlUYJ A RUDH~R PLNT OF THE

CHIIIUln mstUr Carncgie Illst ash PlIll 13U 213 PlImiddot iIlus

(ti) Ross H 1008 DtU ANATO~US(Ht HAU IgtEU lIEXlIuNISClIEN KAtTSCHUKPFLANZ~

OUAUlE PHTHtNllr~1 AltGtNTATU~[ GR Deut Bot Gesell I(r 26a 241-261 illus

(U) SnElt~ 13 lOHI Ttll lILNSITLON FltO~[ ROOT TO STt~1 IN IItllANTHUS ANNUlS L AND

R(Tll1I1 ~(lNrS lJlmNH AII1r )[icl1alld Nat 12 425-187 (7) YnrlE1IllN 1

188middot1 Tim IgtES eOHIOSEES 258 Pl Paris

ar( omewhat fartlJ(l apart C Rnlina train ~o 40G high in rublwT X 28 Slt out ill 1l35 alld nCI irrigntcd _-l and ( are very similar in allllcaranct middot(heing the ~aIllC tmin) aHI irrigation docs not seem to have hnd all~- (tr((( on the structurc D Salinas strain No lV low in rullllel Set out in 1930 and nCCl irrigat(ll X 28 Thc cortex is narrow and the vailnhll storage spacc for ruhber is not a glent as in l and C llut just as grcat as ill B The lliffprCllce lletwetll Band J) SllJllS to lie ihe relatively narrow band of nctive phloem in D as compared with the broad lland in

B E Enlargl(l vipw of xylen and vascular rays of strain No 406 (not irrimiddot gatcd) X ISO P Enlarged yi(w of xylem of strain 49 X 180 Note the larger vessel alld wider rays ill strain No J06 compared with those of strain No -O

ORGANIZATION OF TilE UNITED STATES DEPARTMENT OF AGRICULTURE WHEN THIS PUBLICATION WAS EITIIER FIRST PRINTED OR LAST REVISED

Secretarll of Agmiddoticlllfllre___________ _______ bull _____ bull __ Ullder Secreta 10________ _____ _ ___________ _ Assialt Seclet(lmiddot______ __ bullbull ______ bull _________ _

Director of AUIicIIlflll(I1 ntlI UelIIiOIls _______ bull ___ bull ___ _ Diredol of Fill(III(( _______ _________ _ Director of lerYolllleL_______ ___ bull __ bull____ _ bullbull __ _ DirectOl of lIfoIH1fioll _________________

Directo of El~tellsion Wor ____ bull __ _

Director of Forcign AurilIII1II1al RclllliollS_ -Solicitor______________________________ _ __ _ bull

Librarian ______________________________ _

Chief BIIIC(ll of AIri(-lIl1l1lul E(middotollolllics_______ bull_____ _

Chief Office of Cililian Con~CIt(llion Corps Aclieilies__ CIr ief Office of Ila lit a IlIl OJel( iOIlL ____ _ Atlmillist(ol of AgliclIltlll(I Re~etll(h_____ __ _ Direeo of Foo(l Prodllclion ldlll ill istmlioll _ __ Direcol of Pood Di~rilJlIiollbullldlllillisr(liol __ Plcsidcllt Commodity Creelit Corpoatioll ____________ _ Chief Forcyt Scrri((____________ bull __________________ _

Admillistratol Rlral Rc(rifictlion ~ldilliqr(iOIl

(LAum R WICKAIIil

PAUl II AImiddotPL~JlY GROER B HnL A~I UEL B BumsOl- W A JulP

~e Hoy REm lIous~ SA 1ISJlUlIY

M L WILSON

L A VHE~UR UOBEltT II SnmlJls HAIPn It SHAW 1I0WIII) R ToIUY

FREIl MORRELfbullbull

AUTHUlI B T HATCH lill

K C AlrnT~II M CUFFORIl lOWNS~NIgt

ItOY F IIENllItlCKON

J B HUTSON

LYII~ ( middotATTS

IIRRY LATnRY

This bulletin is a contri)ution froIll

lt1UliCIIII1([ RC~car(middoth ~l(IIillistl(ioll ________ I C AlCHnn lrlll1illi~t(tol

BIrcal of Plallt 111(1118111________________ ____ n ~I SALTER Cllict

Rllbbcl Plant csiUfltiolllJ_____________ 1 BUANDES Chief

Fur ~nle ii ih(l ~tlIHImiddotilllHlpllt of IhwlIlIIPlltS r ~~ (~()(rIIIl1(lIt Irililill IHlit(I 1 n-hiWl()Il U C - lli(l~ 1 ((IH

t

bull

l (II q11 hllIll~h phlplllI 11lt1 IIIiphtI11 xI1I1I1 11 -gt1lilll l11ill Xn Hili Ili in 1111gt1gt01 2 Iild (IIIX 1111 1111 I lilll- 1111d 1 1111111 hllIJd hal d liC ldin~ pltl(lI1l1~ n tllinn~ --llnill ~o -JP lli~11 ill 11IillilI It t 11 I Iil ill 111 ILlI ilritnitti Ih IIIIl 1tlI llId ill Iuil- 1112

(Illfald ilh 1 IIII PIIlX i IlllITI 1I1l1 111 ImiddotIImiddotlllll~IllIItlUl~ l hmiddot hlaL Th Z (Ie ImiddottilI ]1111111111 b 11lt11 lhlll ill1 X~111I1 ll~

33 MORPHOLOGY AD A~ATOMY OF GUAYULE

LITERATURE CITED (1) DANOEARD P A

1881) mCHEBCHES SUR U MOllE UUNION DE LA TrOE 1cT DE TA BAOINE CJn LES DlCOTYLEDONES Botaniste1 75-12fgt

(2) DLNOVA V J SOSNOVElZ A A and SnsHIN N A 1934 CO~LPItATIVE CYTOEMDUYOIOltllCAL ANALYSlS OF TH~ VARUTlES OF

PAITHtNll~[ AllGtNTATU~1 ORAY AND PARTHENIUM INCANUM ORAY JOllr Bot de lUUSSll)(5) 447-466

(3) KOKItA E 1011 lIOllP II 0 LOGY AND Dtnxop~[tNT OF THE INLOR~SCIcNms OF IARTHENIID[

lWENTATU~( O (GUAYULEJ ANIgt OF PAHTHENIU~[ HYSTEHOIHORtS L

~losko Ohsheh ISII Prirody Otd BioI Billl (Soc Nat de MlISCOII Sect BioI Bul [1031]) pp 207-236 375-383

(4) LLOYD F E lUll GUAY1LE (IAITH~olU~( IGtNIATUM GlUYJ A RUDH~R PLNT OF THE

CHIIIUln mstUr Carncgie Illst ash PlIll 13U 213 PlImiddot iIlus

(ti) Ross H 1008 DtU ANATO~US(Ht HAU IgtEU lIEXlIuNISClIEN KAtTSCHUKPFLANZ~

OUAUlE PHTHtNllr~1 AltGtNTATU~[ GR Deut Bot Gesell I(r 26a 241-261 illus

(U) SnElt~ 13 lOHI Ttll lILNSITLON FltO~[ ROOT TO STt~1 IN IItllANTHUS ANNUlS L AND

R(Tll1I1 ~(lNrS lJlmNH AII1r )[icl1alld Nat 12 425-187 (7) YnrlE1IllN 1

188middot1 Tim IgtES eOHIOSEES 258 Pl Paris

ar( omewhat fartlJ(l apart C Rnlina train ~o 40G high in rublwT X 28 Slt out ill 1l35 alld nCI irrigntcd _-l and ( are very similar in allllcaranct middot(heing the ~aIllC tmin) aHI irrigation docs not seem to have hnd all~- (tr((( on the structurc D Salinas strain No lV low in rullllel Set out in 1930 and nCCl irrigat(ll X 28 Thc cortex is narrow and the vailnhll storage spacc for ruhber is not a glent as in l and C llut just as grcat as ill B The lliffprCllce lletwetll Band J) SllJllS to lie ihe relatively narrow band of nctive phloem in D as compared with the broad lland in

B E Enlargl(l vipw of xylen and vascular rays of strain No 406 (not irrimiddot gatcd) X ISO P Enlarged yi(w of xylem of strain 49 X 180 Note the larger vessel alld wider rays ill strain No J06 compared with those of strain No -O

ORGANIZATION OF TilE UNITED STATES DEPARTMENT OF AGRICULTURE WHEN THIS PUBLICATION WAS EITIIER FIRST PRINTED OR LAST REVISED

Secretarll of Agmiddoticlllfllre___________ _______ bull _____ bull __ Ullder Secreta 10________ _____ _ ___________ _ Assialt Seclet(lmiddot______ __ bullbull ______ bull _________ _

Director of AUIicIIlflll(I1 ntlI UelIIiOIls _______ bull ___ bull ___ _ Diredol of Fill(III(( _______ _________ _ Director of lerYolllleL_______ ___ bull __ bull____ _ bullbull __ _ DirectOl of lIfoIH1fioll _________________

Directo of El~tellsion Wor ____ bull __ _

Director of Forcign AurilIII1II1al RclllliollS_ -Solicitor______________________________ _ __ _ bull

Librarian ______________________________ _

Chief BIIIC(ll of AIri(-lIl1l1lul E(middotollolllics_______ bull_____ _

Chief Office of Cililian Con~CIt(llion Corps Aclieilies__ CIr ief Office of Ila lit a IlIl OJel( iOIlL ____ _ Atlmillist(ol of AgliclIltlll(I Re~etll(h_____ __ _ Direeo of Foo(l Prodllclion ldlll ill istmlioll _ __ Direcol of Pood Di~rilJlIiollbullldlllillisr(liol __ Plcsidcllt Commodity Creelit Corpoatioll ____________ _ Chief Forcyt Scrri((____________ bull __________________ _

Admillistratol Rlral Rc(rifictlion ~ldilliqr(iOIl

(LAum R WICKAIIil

PAUl II AImiddotPL~JlY GROER B HnL A~I UEL B BumsOl- W A JulP

~e Hoy REm lIous~ SA 1ISJlUlIY

M L WILSON

L A VHE~UR UOBEltT II SnmlJls HAIPn It SHAW 1I0WIII) R ToIUY

FREIl MORRELfbullbull

AUTHUlI B T HATCH lill

K C AlrnT~II M CUFFORIl lOWNS~NIgt

ItOY F IIENllItlCKON

J B HUTSON

LYII~ ( middotATTS

IIRRY LATnRY

This bulletin is a contri)ution froIll

lt1UliCIIII1([ RC~car(middoth ~l(IIillistl(ioll ________ I C AlCHnn lrlll1illi~t(tol

BIrcal of Plallt 111(1118111________________ ____ n ~I SALTER Cllict

Rllbbcl Plant csiUfltiolllJ_____________ 1 BUANDES Chief

Fur ~nle ii ih(l ~tlIHImiddotilllHlpllt of IhwlIlIIPlltS r ~~ (~()(rIIIl1(lIt Irililill IHlit(I 1 n-hiWl()Il U C - lli(l~ 1 ((IH

t

33 MORPHOLOGY AD A~ATOMY OF GUAYULE

LITERATURE CITED (1) DANOEARD P A

1881) mCHEBCHES SUR U MOllE UUNION DE LA TrOE 1cT DE TA BAOINE CJn LES DlCOTYLEDONES Botaniste1 75-12fgt

(2) DLNOVA V J SOSNOVElZ A A and SnsHIN N A 1934 CO~LPItATIVE CYTOEMDUYOIOltllCAL ANALYSlS OF TH~ VARUTlES OF

PAITHtNll~[ AllGtNTATU~1 ORAY AND PARTHENIUM INCANUM ORAY JOllr Bot de lUUSSll)(5) 447-466

(3) KOKItA E 1011 lIOllP II 0 LOGY AND Dtnxop~[tNT OF THE INLOR~SCIcNms OF IARTHENIID[

lWENTATU~( O (GUAYULEJ ANIgt OF PAHTHENIU~[ HYSTEHOIHORtS L

~losko Ohsheh ISII Prirody Otd BioI Billl (Soc Nat de MlISCOII Sect BioI Bul [1031]) pp 207-236 375-383

(4) LLOYD F E lUll GUAY1LE (IAITH~olU~( IGtNIATUM GlUYJ A RUDH~R PLNT OF THE

CHIIIUln mstUr Carncgie Illst ash PlIll 13U 213 PlImiddot iIlus

(ti) Ross H 1008 DtU ANATO~US(Ht HAU IgtEU lIEXlIuNISClIEN KAtTSCHUKPFLANZ~

OUAUlE PHTHtNllr~1 AltGtNTATU~[ GR Deut Bot Gesell I(r 26a 241-261 illus

(U) SnElt~ 13 lOHI Ttll lILNSITLON FltO~[ ROOT TO STt~1 IN IItllANTHUS ANNUlS L AND

R(Tll1I1 ~(lNrS lJlmNH AII1r )[icl1alld Nat 12 425-187 (7) YnrlE1IllN 1

188middot1 Tim IgtES eOHIOSEES 258 Pl Paris

ar( omewhat fartlJ(l apart C Rnlina train ~o 40G high in rublwT X 28 Slt out ill 1l35 alld nCI irrigntcd _-l and ( are very similar in allllcaranct middot(heing the ~aIllC tmin) aHI irrigation docs not seem to have hnd all~- (tr((( on the structurc D Salinas strain No lV low in rullllel Set out in 1930 and nCCl irrigat(ll X 28 Thc cortex is narrow and the vailnhll storage spacc for ruhber is not a glent as in l and C llut just as grcat as ill B The lliffprCllce lletwetll Band J) SllJllS to lie ihe relatively narrow band of nctive phloem in D as compared with the broad lland in

B E Enlargl(l vipw of xylen and vascular rays of strain No 406 (not irrimiddot gatcd) X ISO P Enlarged yi(w of xylem of strain 49 X 180 Note the larger vessel alld wider rays ill strain No J06 compared with those of strain No -O

ORGANIZATION OF TilE UNITED STATES DEPARTMENT OF AGRICULTURE WHEN THIS PUBLICATION WAS EITIIER FIRST PRINTED OR LAST REVISED

Secretarll of Agmiddoticlllfllre___________ _______ bull _____ bull __ Ullder Secreta 10________ _____ _ ___________ _ Assialt Seclet(lmiddot______ __ bullbull ______ bull _________ _

Director of AUIicIIlflll(I1 ntlI UelIIiOIls _______ bull ___ bull ___ _ Diredol of Fill(III(( _______ _________ _ Director of lerYolllleL_______ ___ bull __ bull____ _ bullbull __ _ DirectOl of lIfoIH1fioll _________________

Directo of El~tellsion Wor ____ bull __ _

Director of Forcign AurilIII1II1al RclllliollS_ -Solicitor______________________________ _ __ _ bull

Librarian ______________________________ _

Chief BIIIC(ll of AIri(-lIl1l1lul E(middotollolllics_______ bull_____ _

Chief Office of Cililian Con~CIt(llion Corps Aclieilies__ CIr ief Office of Ila lit a IlIl OJel( iOIlL ____ _ Atlmillist(ol of AgliclIltlll(I Re~etll(h_____ __ _ Direeo of Foo(l Prodllclion ldlll ill istmlioll _ __ Direcol of Pood Di~rilJlIiollbullldlllillisr(liol __ Plcsidcllt Commodity Creelit Corpoatioll ____________ _ Chief Forcyt Scrri((____________ bull __________________ _

Admillistratol Rlral Rc(rifictlion ~ldilliqr(iOIl

(LAum R WICKAIIil

PAUl II AImiddotPL~JlY GROER B HnL A~I UEL B BumsOl- W A JulP

~e Hoy REm lIous~ SA 1ISJlUlIY

M L WILSON

L A VHE~UR UOBEltT II SnmlJls HAIPn It SHAW 1I0WIII) R ToIUY

FREIl MORRELfbullbull

AUTHUlI B T HATCH lill

K C AlrnT~II M CUFFORIl lOWNS~NIgt

ItOY F IIENllItlCKON

J B HUTSON

LYII~ ( middotATTS

IIRRY LATnRY

This bulletin is a contri)ution froIll

lt1UliCIIII1([ RC~car(middoth ~l(IIillistl(ioll ________ I C AlCHnn lrlll1illi~t(tol

BIrcal of Plallt 111(1118111________________ ____ n ~I SALTER Cllict

Rllbbcl Plant csiUfltiolllJ_____________ 1 BUANDES Chief

Fur ~nle ii ih(l ~tlIHImiddotilllHlpllt of IhwlIlIIPlltS r ~~ (~()(rIIIl1(lIt Irililill IHlit(I 1 n-hiWl()Il U C - lli(l~ 1 ((IH

t

ORGANIZATION OF TilE UNITED STATES DEPARTMENT OF AGRICULTURE WHEN THIS PUBLICATION WAS EITIIER FIRST PRINTED OR LAST REVISED

Secretarll of Agmiddoticlllfllre___________ _______ bull _____ bull __ Ullder Secreta 10________ _____ _ ___________ _ Assialt Seclet(lmiddot______ __ bullbull ______ bull _________ _

Director of AUIicIIlflll(I1 ntlI UelIIiOIls _______ bull ___ bull ___ _ Diredol of Fill(III(( _______ _________ _ Director of lerYolllleL_______ ___ bull __ bull____ _ bullbull __ _ DirectOl of lIfoIH1fioll _________________

Directo of El~tellsion Wor ____ bull __ _

Director of Forcign AurilIII1II1al RclllliollS_ -Solicitor______________________________ _ __ _ bull

Librarian ______________________________ _

Chief BIIIC(ll of AIri(-lIl1l1lul E(middotollolllics_______ bull_____ _

Chief Office of Cililian Con~CIt(llion Corps Aclieilies__ CIr ief Office of Ila lit a IlIl OJel( iOIlL ____ _ Atlmillist(ol of AgliclIltlll(I Re~etll(h_____ __ _ Direeo of Foo(l Prodllclion ldlll ill istmlioll _ __ Direcol of Pood Di~rilJlIiollbullldlllillisr(liol __ Plcsidcllt Commodity Creelit Corpoatioll ____________ _ Chief Forcyt Scrri((____________ bull __________________ _

Admillistratol Rlral Rc(rifictlion ~ldilliqr(iOIl

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PAUl II AImiddotPL~JlY GROER B HnL A~I UEL B BumsOl- W A JulP

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M L WILSON

L A VHE~UR UOBEltT II SnmlJls HAIPn It SHAW 1I0WIII) R ToIUY

FREIl MORRELfbullbull

AUTHUlI B T HATCH lill

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J B HUTSON

LYII~ ( middotATTS

IIRRY LATnRY

This bulletin is a contri)ution froIll

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BIrcal of Plallt 111(1118111________________ ____ n ~I SALTER Cllict

Rllbbcl Plant csiUfltiolllJ_____________ 1 BUANDES Chief

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