Tropical Woods

Home , Baccharis angustifolia, Grindelia stricta, Heterotheca grandiflora, Lepidospartum squamatum, Olearia, Olearia paniculata

TROPICAL WOODS

NUMBER 113 pp. 54-84 OCTOBER, 1960

WOOD ANATOMY OF ASTEREAE (COMPOSITAE)

SHERWIN CARLQUIST 54 TROPICAL WOODS 1960

WOOD ANATOMY OF ASTEREAE (COMPOSITAE)

SHERWiN ARLQUIST1 Claremont Graduate School, Rancho Santa Aria Botanic Garden, Claremont, California The woody Astereae utilized in this study account for more woody species than have been, or will be, studied in connection with any other single tribe of Compositae. The abundance of wood samples available for Astereae is not the result of a large number of woody genera. Indeed, the Heliantheae or Mutisieae possess larger nuinbers of woody genera. The bulk of Astereae studied here are representa tives of only a few genera: Baccharis, Chrysothamnus, Haplopappus, and Olearia. These large genera, many species of which are woody, have permitted an emphasis on patterns of wood evolution within genera as well as within the tribe as a whole. The Astereae, more than any other tribe, offer a clear picture of the parallelisms in wood evolution which are so abundant in Compositae, and which complicate analysis in terms of systematic relationships. On these accounts, Astereae may be considered a module, albeit with its own special features, of wood evolution in a highly specialized family. Despite the abundance of woody species in Astereae, a remarkable paucity of literature concerned with wood anatomy of members of this tribe exists. Metcalfe and Chalk (1950) refer to a few characteristics in the genera (no species given) Baccharis, Ericameria (treated here under Haplopappus), and Olearia. Webber (1936) offers a very limited amount of data for Chrysothanmus nauseosus ssp. mohavensis and Aster carnosus. In a semi-floristic study, the writer (1958b) offered full descriptions of the woods of Baccharis angustifolia, B. halimifolia, and Haplopappus phyllocephalus var. megacephalus. Because some genera of Astereae have been considered close to, or referable to ‘This research was supported by a grant from the National Science Foundation, NSFG—5428. The writer wishes to express sincerest appreciation for this aid, which is permitting completion of studies on wood anatomy of Compositae and related families. No. 113 TROPICAL WOODS 55

Heliantheae, the writer (1958a) included Eastwoodia elegans and Grindelia stricta ssp. procumbens in his study on wood anatomy of that tribe. Unfortunately the organization of tabular material in that paper appears to group these two species under the heading “Ambrosiinae.” The two species were merely included at the end of the table, and should have been set off by themselves. Textual reference makes it clear that at no time did the writer consider them as mem— hers of Ambrosiinae; the evidence of the present study suggests, in fact, that they are best treated under Astereac. Because tabular data on these two taxa has already been given, they are not included here in table 1. Hardly any material other than the references cited above gives anything but the most scanty data on wood anatomy of Astereae. New World woody Astereae are mostly shrubs character istically found in semi-arid or arid habitats. In this category may be included Baccharis (North and South America). Haplopappus (North and South America), Chrysothamnus (North American deserts), Gutierrezia (southwestern U. S., Mexico, South America), and Lepidosparturn (southern California). Some of these genera (Baccharis, Chrysothamnus, Haplopappus) include herbs as well as woody plants, and some species which must be termed herbs (Aster, Conyza, Grindelia, Heterotheca, and Solidago) have been included in this study because sufficient xylem was available. Conyza canadensis and Heterotheca grandiflora are annuals. Among the Old World genera, Olearia is outstanding in its number of species and in its diversity of habit. Although some species are herbaceous, most are shrubs or trees. Some of the latter are small trees of a definite arboreal woody habit. Although Olearia is best represented in Australia and New Zealand, a few species occur on other South Pacific islands. Tetramoloplum humile is an alpine, mat-like, peren nial herb which occurs on the Hawaiian Islands, as do other species of that genus. Psiadia rotundifolia is one of the several curious extinct or vanishing endemic arboreal Corn— positae of St. Helena Island. Likewise, Remya rnauiensis, one of two species of this endemic Hawaiian genus, is a shrub of great rarity from the rain forests of Maui.

C. D. Washington, Institution, sonian

Smith Woods, of the Division to has sent been here studied

the species slides of of set A (1958a). writer the by earlier

described as those same the are preparation of Methods

METHODS

G. Diboll. Mr. Alfred or Quibell

Charles F. Mr. by prepared were this study for sections

the of Most recognized). not are of Haplopappus genera

segregate (e.g., species of other treatment influenced has this

(1959); Keck and Munz of that flora follows California the

in occur which species of Nomenclature (1959). Chambers

and Stern of abbreviations the with accordance in cited

numbers. collection wood (2) and (1959); Stafleu and jouw

Lan to according abbreviation herbarium the with gether

to known, were such if and number, name (1) collector’s

by identified are specimens 1, In table specimens. barium

her from or Garden, Botanic Ana Santa Rancho the in

cultivated specimens derived from were samples Still other

California. southern in abundant arc Astereae woody since

the writer, by field the in collected were samples tional

addi of number A acknowledged. is gratefully individuals

these generosity of The Berkeley. California, of University

Flerharium, the Jepson of member staff Robbins, G. Thomas

Mr. late the by provided was of Grindelia sample cuneifolia

The region. that in species of Olearia samples sent land,

Zea New Whakarewarewa, Service, Forest Zealand New

the of H. Orman R. Dr. Australia. Melbourne, South zation,

Organi Research Industrial and Scientific Commonwealth

Products, Forest of Division the of Ingle H. D. Dr. by nished

fur i’as of species Olearia Australian of Material tution.

that insti— of formerly L. Stern, Dr. of William kindness the

J. through University Yale of collection Record Samuel

the from was provided material the of bulk The study.

this for utilized sources were several from samples Wood

MATERL4LS ACKNOWLEDGMENTS AND

1960 WOODS TROPICAL 56 Fig. 1—4.—Fig. 1, 2. Baccbaris angustifolia.—Fig. 1. Transection. Note band of thick-walled fibers, prominent zones of parenchyma around vessels was well as apotracheal parenchyma.—Fig. 2. Tangential section. Note wide zone of parenchyma at right of vessel—Fig. 3, 4. Raccharis rosrnarinifolia.—Fig. 3. Transection. Note zonation of vessels in rings and patches.—Fig. 4. Tangential section, showing storied fibers. All, )< 65. No. 113 TROPICAL WOODS 57

ANATOMICAL DESCRIPTIONS Table 1 contains a summary of characteristics considered to be significant in comparing species of Astereae with each other and with other Compositae. Features difficult to sum marize in chart form, or which occur in a few species only, are discussed under appropriate histological headings below.

Explanation of symbols in table 1: cb = coarse bands on vessel walls cg = continuous grooves, i.e., grooves which form extended helices around vessel walls f = libriform fibers fb = fine bands on vessel walls g = grooves interconnecting two or several pits in a helix my = more numerous vessels p = axial parenchyma r = vascular rays tf = thin-walled fibers v = vessel elements Vt = vascular tracheids wv = wider vessels + = present, characteristic — = present to a limited extent 0 = absent

VESSELS I)imensions.—A figure for average diameter of vessel elements is given in table 1. .‘Vhere vascular tracheids occur, this figure is naturally very difficult to determine. Measure ments of vessel-element width were made at the widest point, and included the wall of vessels seen in transection. The figure for average vessel diameter illustrates the rela tively small diameter of vessels in most Astereae: species in which the average diameter is less than 50 are in the majority. This contrasts with Cichorieae (Cariquist, 1960), hut not with Helenieae (Cariquist, 1959). If the diameter of the widest vessel is determined (first column, table 1), this figure is found to reflect the average diameter hut also 58 TROPICAL WOODS 1960

Table I. WooD CHARACTERS n AsrEiuAR

SPECIES COLLECTION Aster spinosus Benth. Detweiler 36 (F) (Yw-26691) Baccharis angustifolia Michx. Stern& Chambers 250 (Y,RSA) (Yw-51462) B. cassiniaefolia DC. Rimbach 837 (Y) (Yw-34188) B. concava Pers. (Yw-34037) B. glomerulifolia Pers. MacDonald 5267 (Y) (Yw325o4) B. halimifolia L. Stern & Brizicky 263 (Y,RSA) (Yw-5 1101) B. halirnifolia L. Stern & Brizicky 292 (Y,RSA) (Yw-51122) B. halimifolia L. Stern & Brizicky 398 (Y,RSA) (Yw-51199) B. halimifolia L. Stern & Brizicky 424 (Y,RSA) (Yw-5 1219) B. lanceolata H.B.K. (Yw-16940) B. myrsinites (Pers.)Lam. (Yw-7262) B. sicglecta Britt. Wilson 1477 (F) (Yw-50570) B. obtusifolia H.B.K. Rimbach 156 (Y) (Yw-24095) B. patagonica H.&A. (Yw-1770) B. pilularis DC. ssp. Carlquist 492 (RSA) consanguinea (DC.) C. B. Wolf B. Plummerae Gray Wolf 4404 (RSA) B. polyantha H.B.K. (Yw-16910) B. rosmarinifolia H.&A. (Yw-49852) B. sergiloides Gray Carlquist 430 (RSA) B. thesioides H.B.K. Detweiler 32 (Y) (Yw-14757) B. viminea DC. Cariquist 289 (RSA) Chrysothamnus latisquarnaeus (Gray) Derweiler 22 (F) (Yw-26677) Greene C. nauseosus (Pall.)Britt. ssp. Cariquist 436 (RSA) consimilis (Greene)Hall & Clem. C. nauseosus (Pall.) Britt. ssp. Wolf 2506 (RSA) consimilis (Greene) Hall & Clem. C. paniculatus (Gray)Hall Balls & Everett 23177 (RSA) C. teretifolius (Dur.&Hilg.) Hall Cariquist 329 (RSA) No. 113 TROPICAL WOODS 59

Table 1. WooD CHARACTERS IN ASwREAR

— Ci)

C I 76. 30.7 3.27 216 302 g 0 0 .65 193 0 + 2.33 76. 43.2 1.52 181 291 cg,fb 0 p,f .26 90 + — 30.0 120 73.4 2.32 270 522 cg,fb 0 0 .21 129 + 0 2.54 108 40.2 223 263 cb inv,wv,tf p,fp .24 92 + 0 2.31 97 33.1 143 246 fb 0 v,vt,v,f .30 119 + 0 3.07 85 44.5 2.07 214 223 g,fb 0 v,p,f .32 158 ± — 2.66 86 35.6 3.73 208 319 g,fb wv v,vt,p,f .28 148 + 0 2.32 76 45.7 3.03 184 365 g,fb wv v,p,f .50 145 + 0 2.72

76 46.4 1.77 204 416 g,fb 0 0 .32 114 + — 2.54 43 18.0 co 192 313 cb wv v,p,f .28 92 + + 2.60 59 39.4 2.06 276 535 cg,fb 0 v,p,f, .23 146 + + 2.08 130 38.5 o 174 277 cg,fb wv p .38 54 + 0 3.15 54 22.4 o 217 274 cg,cb 0 v,vt,p,f .28 131 + — 2.14 59 26.1 176 278 cb rnv,wv v,vt,f .17 62 + 0 2.44 86 37.8 6.10 135 320 cg,fb my v,p .25 61 + — 2.94 76 33.9 4.73 164 265 fb rnv,’wv 0 .41 101 + + 2.78 97 49.5 3.39 199 369 fb 0 0 28 79 + + 3.04 86 40.5 3.11 178 201 cb WV,p v,vt,p,f .41 94 + 0 3.66 67 35.8 4.27 128 248 fb 0 v,vt,p,f .30 92 + 2.60 115 39.1 o 174 313 Cl) WV v,vt,p,f .53 64 + 0 4.14 92 32.2 184 283 cb WV f .45 96 + — 3.08 88 34.3 135 188 0 WV v,vt,p 1.14 + 0 5.36 97 36.8 55 250 0 wv v,vt,p,f .69 + o 7.24

75 32.7 132 369 0 WV V,Vt, .61 + 0 9.65

86 25.5 o 126 254 fb wv v,vt,p .74 + —5.04 78 38.2 oc 124 191 fb WV v,vt,p,f .75 100 + 0 3.85

(Y) f. (Yw-50347) 54 (A.Rich.)Hook. furfuracea 0. Hambling

f. 0. Hook, Cunninghamii (Aw-3455J)

f. Hook. 0. avicenniaefolia (FPAw-12072)

Mud. F. (Aw-21634) phylla argo 0.

F. (FPAw-6115) Mud. 0. argophylla

F. (FPAw-4216) Mud. 0. argophylla

Muell. F. (FPAw-2000) argophylla 0.

(A) Aw-21632) 163 Muell. F. argophylla McVaughcen Olearia

Gray (Gray)

(RSA) 621 squamatum Carlquist Lepidospartum

(RSA) Nutt. 618 Cariquist grandiflora Heterotheca

(Yw-4888A) 1919 Gray Garratt, Watsonii H.

(Nutt.)Hall vernonioides

(RSA) 495 ssp. (H.B.K.) Blake Cariquist venetus H.

(DC.) Keck grindelioides

(RSA) 18555 & Everett H.&A. Balls ssp. H. squarrosus

(RSA) 491 Gray Cariquist pinifolius I-I.

(Nash)Hall megacephalus

(Yw-5 1261) (Y,RSA) 342 & var. Brizicky DC. Stern phyllocephalus H.

(RSA) (Greene)Blake 19779 Balls Parishii H.

(POM) 4893 & Demaree Blake Wiggins martirensis H.

(POM) IV-14-1903 Gray Jones laricifoliux H.

(RSA) 21446 Balls (Less.)H.&A. ericoides H.

(RSA) 455 Carlquist (Gray)Blake cams H.

(Greene)Blake

(RSA) 431 Cariquist acradenius Haplopappus

(RSA) 630 Carlquist (DC.) Gray microcephala 0.

(POM) VIII-31-1924 Johnston Gray (DC.) microcephala Qutierrezia

(JEPS) 3941 Robbins Nutt. cuneifolia Grindelia

(RSA)

619 Carlquist (L.) Cronq. canadensis yza Con

COLLECTION SPECIES

1—Continued Table

1960 WOODS TROPICAL 60 Fig. 5—8—-Fig. 5. Baccbaris patago?IiCa, transection. Note growth rings beginning hCIO\V center, prominent aggregations of vessels—Fig. 6. Raccl,aris siiyrsi’niteS. tangential section. Rays are narrow and vaguely storied, as are ibers.—Fig. 7, 8. Baccbaris /mceolafa.—Fig. 7. Transection. Note two growth rings helo\v center-—Fig. 8. Tangential section. Filiers are storied, although somewhat irregularly All, x 65. No. 113 TROPICAL WOODS 61

Table 1—Continued

84 0 0 + + 3.12 75 2.64 132 276 g 0 0 .79 + + 5.91 43 25.6 cc 145 275 cg,fb WV Vt .52 + + 3.06 54 27.6 oc 182 263 g,fb WV Vt .88 + + 3.44 75 26.8 00 148 274 0 my 0 1(X) 60 + + 4.15

86 29.8 00 137 298 0 WV, 0 35 83 + + 2.24 75 36.4 169 278 g,cg WV v,vt,p 1.32 + + 4.24 65 28.3 cc 135 319 g,fb WV 0 1.35 + + 4.88 65 28.9 cc 153 231 g,cb mv,p v,vt,p,f .64 137 + + 2.82 129 39.1 co 182 341 g,fb flV,”.v v,p,f .92 + 0 5.12 53 27.3 3.22 114 224 0 0 0 .46 78 4.60 — + 72 32.1 248 cc 160 g mv,p 0 .82 84 + — 5.29 84 35.2 2.17 123 270 g • 0 .39 76 + + 3.72 65 28.8 4.00 132 154 0 wv,f 0 .69 + + 5.29

62 27.0 00 106 210 0 wv 0 .57 + + 5.27 87 49.2 3.50 176 386 0 0 0 .3960+ + 3.00 135 49.9 cc 164 346 0 wv v,vt 1.79 + + 4.64 97 60.3 2.11 163 205 g,fb 0 v,p,f .29 + + 4.08 92 445 2.78 331 415 g,fb if v,p,f .48 73 + + 3.28 86 55.8 2.30 229 258 g,fb 0 v,p,f .42 100 + + 2.95 81 49.7 2.50 260 313 g,fb 0 v,p,f .41 83 + + 3.75 112 66.7 2.06 269 302 cg,fb p,tf v,p,f .64 95 + + 3.62 85 35.0 cc 204 239 cb wv v,vt,p,f .31 49 + (1 3.16 119 60.0 310 3.03 403 0 0 v,p,f .28 + — 3.49 92 219 29.4 oc 261 cb wv v,p,f .28 + — 4.20 62 TROPICAL WOODS 1960

Table 1—Cornrmed

SPECIES COLLECTION 0. ilicifolia Hook. f. (A-2612J) 0. ilicifolia Hook. f. J. M. Harris s.n. (WZw) 0. lacunosa Hook f. J. M. Harris s.n. (WZw) 0. Muelleri Benth. (FPAw-9745) 0. nitida Hook. f. (Aw-2610J) 0. nummularifolia (Hook.f.)Hook f. Hambling 5 (Y) (Yw-50350) 0. pachyphylla Cheesem. Hambling 62 (Y) (Yw-50350) 0. paniculata (Forst.)Cheesern. J. M. Harris s.n. (WZw) 0. paniculata (Forst.) Cheesem. (Yw-48145) 0. pimeleoides Benth. (FPAw-6091) 0. rani (Cunn.) Druce J. M. Harris s.n. (WZw) 0. rani (Cunn.)Druce var. Hambhing 30 (Y) (Yw$0348) colorata (Col.)T. Kirk 0. Solandri Hook. f. (Aw-2613J) 0. teretifolia F. Much. (FPAw-9747) 0. virgata Hook f. J. M. Harris s.n. (WZw) Psiadia rotundifoHa Hook. f. (Yw-29783) Remya mauiensis Hillebr. Forbes 2267M (BISH) (Yw-26360) Solidago spathulata DC. Balls 19753 (RSA) Tetramoloplum humile Hillebr. Cariquist H18 (UC) ‘0 ‘0 SM 0’ C -4-- 00 ‘0 --3 — -4-. ‘.2 - C - a DIAMETER %‘JDES UVESSEL, jh SMJ l.3 00 ‘i Sn 004-.’ ‘-‘0% 0% ‘. ‘—i ‘0 SM Sn C C z — .k. ‘Si sS SM Sn ‘.3 4-3 ‘.3 ‘J3 ‘.3 T’.J —n .—. ‘.a ts si I’S .‘sS — ‘Si Sn ‘St ‘Si Os Os 0 0004--.’ . CC P DIAMETER VESSELS, AVERAGE, —

%55 8888 VESSELS PER GROUP. AVERAGE

— — 4-. — ItS 4--.’4--.’— 4-.’ 4-3 4-3 SM — * — — LENGTH VESSEL ELEMENTS, 00 I’.) — -4 I.J ‘Si tO SM SM 0% ‘0 SM — 4--.’ .4 - ‘—4 ‘0 Os 0 —I ‘0 ‘--1 -II’.’ ‘-‘-30’— —0’ C Sn 005 AVERAGE j ItJ - SM SM SM 4-5’. SM SM I’. 4’. -P 4-3 — 4--.’ 4’. LENGTH LIBRIFORM FIBERS, — S-n Os Os -J Oi .P’0 ‘04--J0 00004--.’ C tn 0% 0% ‘-fl -P ‘3 — -P QO SM - - 000 0’ - - C AVERAGE IL 0QB0 8 . . 0 HELICAL SCULPTURE ON VESSEL WALLS 10

C C ELEMENTS DISTINGUISHING EARLY WOOD IN RINGS 0

. - - STORIED ELEMENTS I -, .-‘ - z,t.4- -t - %% HEIGHT MULTISERIATE RAYS 4%) ‘.53 SM — 4--.’ ‘53 tI SM Sn 1) 1) 4’. - ‘00% 0 I—i SM - .‘000’ 0 -.04---’ ‘0 AVERAGE, MM. ‘.04’- ‘0 Sn Sn 00 HEIGHT UNISERIATE RAYS, .QSM C 1’-.’1%) 0% AVERAGE, RAY CELLS ISODIAMETRIC 0+ 0++++ I ++++++++ +++ TO PROCUMBENT RAY CELLS ISODIAMETRIC it TO ERECT -J ,‘.S SM X t’J 4-3 SM 4-34--.’ 4-5 SM ‘.3 SM SM SM SM SM MAXIMUM WIDTH MULTISERIATE - . ‘si 0 ‘ C 4-.’ .5000 ‘0 ‘SiC ‘s3 ‘.5.4- ‘. RAYS, AVERAGE, CELLS 64 TROPICAL WOODS 1960 to suggest the upper extreme. Thus, only the following species had any vessels which exceeded 100 in diameter: Baccharis cassiniaefolia, B. concava, B. neglecta, B. thesi oldes, Haplopappus Parishii, Lepidospartum squamatum, Olearia argophylla (one collection), 0. Cunninghamii, 0. ilicifolia, 0. nitida, 0. rani, 0. rani var. colorata, 0. irgata (fig. 23), and Psiadia rotundifolia (fig. 27). In five species the widest vessel diameter was less than 50: Baccharis lanceolata (fig. 7, 8), Gutierrezia microcephala, Olearia 14uelleri, 0. pimeleoides (fig. 21, 22) and Tetramolopium humile (fig. 9, 10). Many Astereae, as the list of species below which possess vascular tracheids suggests, possess vessels which grade down to very narrow widths. With respect to vessel-element length, a surprising num ber of species have an average element length of less than 15Oi, and very few exceed 3OOL in average element length. Certainly the tribe contains no species, as do Fleliantheae and Mutisieae, in which the vessel-element length averages more than 400. The shorter vessel elements of Astereae may be ascribed to the higher phyletic position of this tribe in Compositae or to the fact that many of the species may have shown accelerated specialization with respect to more arid habitats. Certainly extremely small size of vessel elements, as in Tetramolopium humile (fig. 9, 10) seems related to the alpine conditions under which that species lives. Related to diminution in vessel diameter is the frequency of vascular tracheids. Also, vascular tracheids seem fre quent in woods in which large groupings of vessels—some of which are narrow—are present (fig. 7, 21, 23). Vascular tracheids were noted in the following species: Baccharis angustifolia, B. glomerulifolia, B. halimifolia, B. lanceolata, B. obtusifolia, B. patagonica, B. rosmarinifolia, B. sergiloides, B. thesioides, Chrysothanmus latisquarnaeus, C. nauseosus spp. consimilis (fig. 13, 14), C. paniculatus, C. teretifolius (fig. 15), Gutierrezia microcephala, Haplopappus ericoides, H. martirensis, H. Parishii, H. venetus ssp. vernonioides, Lepidosparturn squamatum, Olearia avicenniaefolia, 0. num— inularifoha, 0. pirneleoides (fig. 21, 22), 0. teretifolia, 0. •virgata (fig. 23, 24), and Tet’rarnolopiwn humile (fig. 9, 10). Fig. 9—12——Fig. 9, 10. 7etramolopii/n7 Jiumile._Fig. 9. Transection. \unierous narrow vessels and vascular trachcids arc prcsent.—Fig. 10. langential section. Nearly all elements in the axial portion of the xvleni arc vessel elements or vascular trachcids.—Fig. II, 12. Grindelia stricta ssp. procum/ens.—Fig. 11. Transection. ote tendency toward radial arrangement of vessels—Fig.12. langential section, showing absence of nniseriate rays, and non—storied, thin—walled fibers. All, x 65. No. 113 TROPICAL WOOI)S 65

Pitting.—Dirnensions of pits were measured for each species, although these figures do not appear in table I. Diameter of the pit cavity of intervascular pits proved to be between 4 and 6 for most species. Exceptionally small pits (ca. 3) were observed in Baccharis myrsinites, B. piiv loris, Chrysotbamnus paniculatus, Haplopappus canus, H. megacephalus, and Olearia Muelleri. Pits of Psiadia rotundi folio measured about in diameter. Exceptionally large pits (ca. 7 in diameter) were observed in Chrysothamnus latis quarnaeus, Olearia Cunningharnii (fig. 36), 0. nitida, and 0. paniculata. Intervascular pits in Compositac are typically circular, alternately arranged, and with an oblique elliptical nperture, the long axis of which is only slightly shorter than the diameter of the pit cavity. Pit apertures on some vessels in the genera Chrysothamnus and Lepidospartum, however, are circular, and are thus reminiscent of coniferous bordered pits. In addition, some pit apertures in Lepidospartum have apertures which form shallow grooves longer than the diameter of a pit cavity, but not extending to other pits on the wall. Helical sculpture.—As table 1 shows, Astereae are excep tional among Cornpositae in the degree to which helical sculpture in vessels of the secondary xylem is represented. There are a number of cases in which shallow grooves. formed on the innermost face of the pit aperture, connect two or more pits adjacent in a helix. Such a condition, denoted by “g” in table 1, is found in Olearia Cunninghamii (fig. 36) and has been figured earlier by the writer for Hymenoclea salsola (1958a) and Pluchea odorata (1958h). Because of seemingly transitional cases, and for reasons of close taxonomic affinity, the type just described seems related to a more elaborate type of sculpture in which pairs of fine hands or ridges are present, usually one ridge on either side of a groove interconnecting pits. This latter type of sculp ture is figured here for Olearia argophylla (fig. 37), and in a more prominent form, where the fine bands form continu OUS helices, for Baccharis angustifolia (fig. 34) and Haplo pappus laricifolius (fig. 40). These fine bands, ifiustrated earlier by the writer (1958a) for Eastwoodia elegans, sug

the in are distinctive Astereae shows, 1 As table Astereae. in

importance great assumes feature this 1938), Tippo, (e.g.,

a specialization considered been has vessels of grouping

in increase Because grouping. vessel of patterns and extent

in both diversity a remarkable show Grouping.—Astereae

this tribe. of woods in ization

of special degree greater a for might argue Astereae in them

of absence perforation, scalariform the of alteration an fact

is in in Compositae common so perforation multiple bizarre

If the plate. perforation single a on seen was perforation

the bisecting bar single a mentioned, instance the in seen,

plate perforation suhcircular simple a but anything was folia)

cunci (Grindelia instance one In only Astereae. in absent

lv conspicuous they are 1960), (Cariquist, Cichorieae as

such Compositae, other certain in plates multiple-perforation

bizarre of abundance the plates._Despite Perforation

communication). personal Bailey,

(I. ‘\V. at large families in dicotyledonous have to seems it

as Compositae. in many times occurred probably has spirals

these of modification and Acquisition sense. evolutionary an

in rapid, is type probably specialized most the to transition

and that other, of each modifications progressive are types

various the that 1938), Tippo, with agreement (in dition

con a non-sculptured from a specialization represent do

sculpturings helical that suggests fact This genus. single a in

occur may absence, complete as well as sculpture, helical of

types these all and Olearia, as Baccharis such genera, large in

is that clearly so illustate Astereae which feature curious

1957). The (Carlquist, leiocephala Flotovia as such positac,

Corn other for illustrated been have They 38). (fig. phylla

pachy and Olearia 35), (fig. patagonica as Baccharis such

species, many in were observed bands Such coarse them.

run to benveen seem and a wall, vessel on of pits helices the

as number same about the of are bands conspicuous These

present. are bands coarse which in that final type, a lead to

to seems sculpturing helical in specialization Progressive

gymnoxiphium. for Wilkesia 958a) (1 illustrated was form

different A somewhat respect. one this in at least Astereae,

of a member as best regarded is genus that gest that

1960 WOODS TROPICAL 66 No. 113 TROPICAL WOODS 67 great number of species which possess groupings of very numerous (“os”) vessels. In some of these, early wood may exhibit smaller numbers of vessels per group, whereas late- wood, where vessels are smaller, have the extremely large groupings. Species with this condition include: Bacchoris thesloides, B. virninea, Chrysothamnus (all species), Gutier rezia microcephala, Haplopappus acradenius, H. canus, H. martirensis, H. Parishii, H. pinifolius, H. Watsonii, Lepido spartum squarnatum, Olearia avicenniaefolia, 0. furfuracea, 0. nummularifolia, 0. paniculata, 0. rani, 0. teretifolia, and 0. virgata (fig. 23). The remaining species with large vessel groupings have such large groups throughout the entire xylem. Mostly solitary vessels, shown in fig. 17 for one collection of Olearia argophylla, are, in fact, exceptional in Astereac. Aggregation of a few vessels may take the form of clusters, as in Baccharis angustifolia (fig. 1). Larger clusters are illus trated by Olearia paniculata (fig. 25). Tendency toward formation of radial rows is shown by one collection of Olearia argophylla (fig. 19), Grindelia stricta ssp. procum bens (fIg. 11), and Psiadia rotundifolia (fig. 27). Formation of tangential aggregations of vessels is suggested by Baccharis rormarinifoiia (fig. 3), and more prominently, Olearia Sokindri (fig. 16) and Chrysothamnus nauseosus ssp. con similis (fIg. 13). Large aggregations of vessels often take a zig-zag or diagonal form, both in Baccharis and Olearia. Illustrations of this condition are furnished by Baccharis patagonica (fig. 5), and in a more extreme form, B. lanceolata (fig. 7). The beginning of diagonal patches is suggested in Olearia paniculata (fig. 25), but is more prominently repre sented in other Olearia species: 0. pirneleoides (fig. 21) and 0. virgata (fig. 23). The most extreme expression of vessel aggregation is the abundance of vessels to the virtual exclu sion of other axial cells, with the exception of parenchyma. Tetrarnolopium humile (fig. 9, 10) possesses few libriform fibers; most of the axial portion of the xylem consists of narrow vessels and vascular tracheids. These prominent tendencies toward vessel aggregation exceed those in other groups of Compositae, as figures on vessels per group in TROPICAL WOOI)S 1960 the writer’s earlier papers have shown and such figures in forthcoming papers will also indicate.

LIBRIFORM FIBERS Figures for length of libriform fibers are given in table 1. As might be expected, the average length of libriform fibers in any given species exceeds that of vessel elements. Libri form-fiber dimensions are variable within a species, as the two collections of Olearia argophylla (fig. 17, 18; fig. 19, 20) show. In fig. 17 and 18, extremely short, wide fibers, some of which are septate, are illustrated. These contrast with the narrow, long, thicker-walled fibers shown in fig. 19 and 20. Zones of axial parenchyma cells which appear like short, wide, thin-walled fibers are shown for Baccharis angustifolia (fig. 1, 2), and Psiadia rotundifolia (fig. 27, 28). Such “dimorphic fibers” were also observed in Olearia furfuracea. Special features of libriform fibers which deserve mention include instances of very thin walled fibers. This feature occurs in several collections of Olearia argophylla, such as that shown in flg. 17. Baccharis neglecta is notable for its rings of very thin-walled fibers. Especially thin-walled fibers (walls down to in thickness) characterize the genus Grindelia (fig. 11, 12), and Conyza canadensis. Mostly, fiber wails of Astereae range between 2 and 5,.2. in thickness. Particularly thick walls (6 or more in width) were ob served in Baccharis concava, B. lanceolata (fig. 7, 8), Chryso thamnus latisquamaeus, Gutier’rezia microcephala, Haplo pappus laricifolius, Olearia paniculata (fig. 25, 26), 0. pirneleoides (fig. 21, 22), 0. rani, and Psiadia rotundifolia (fig. 27, 28). in width, libriform fibers of most Astereae range between 20 and 35. Exceptions to this includes cases of extremely narrow fibers (averages given in parentheses): Baccharis lanceolata (1 3), Haplopappus phyllocephalus var. megacephalus, (l4.6), H. pinifolius (17.5p.) and Olearia Muelleri (1 5.8k). Most species of Baccharis and Haplopappus do not exceed 22i in average fiber width. Exceptionally wide fibers (more than 35) occur in the following species: Grindelia cuneifolia (39.8), Olearia argophylla (45.9 in the collection illustrated in fig. 17; 35.9.t and 38.9, in two Fig. 1 3—16.-_--Fig. 13, 14. Chrysothamnus nauseosus ssp. consinnlis Vol 2O6.—Fig. 13. Transection. Note end of growth ring, left, prominent aggregation of vessels and vascular tracheids.—1ig. 14. Tangential see— non. I arge iriultiseriate rays are present cxclusively.-_lig. 15. Cbrso thamnus teretifolius, tangential section. Narrow multiscriate rays are present exclusivelv.—_Fig. 16. Olearia Solandri, transection. Vessels tend to be aggregated into tangential bands. All. x 65. No. 113 TROPICAL WOODS 69 other collections, respectively), and 0. Cunningharnii (37.7). Because of their staining reactions and shrinkage, libri form bers in Baceharis pilularis and both species of Grin- delia examined may be termed gelatinous. Septate fibers arc abundant in 0. Cunningharnii.

AXIAL PARENCHYMA Apotracheal parenchyrna.—Attention has been called in earlier papers to the occurrence in Compositae of bands of short prosenchylnatous elements which must be termed axial parenchyma. These bands are particularly characteristic of certain Heliantheae (Cariquist, 1 958a). Such bands have been noted for the Astereae Baccharis angustifolia and B. halimi folia (Carlquist, 1958b). Parenchyrna bands which must be termed marginal parenchyma occur in Baccharis polyantha, B. rosmarinifolia, B. sergiloides, Haplopappus canus, and Psiadia rotundifolia (fig. 27). Partial bands of axial paren chyma, like the axial parenchyma which is paratracheal in distribution, occur in apotracheal bands in Baccharis halimi folia. Such parenchyma bands, in which there are transitions between apotracheal and paratracheal, have been figured by Metcalfe and Chalk (1950) for Baccharis tucumanensis. Such paren.chyma distributions are characteristic, to some degree, of all of the species of Baccharis. Occurrence of bands of apotracheal parenchyma in Astereae appears to be related, at least to some degree, to occurrence of abundant vasicen tric parenchvma (e.g., Psiadia rotundifolia, fig. 27). A feature of considerable interest is the occurrence in axial portions of xylem of some species of a number of scattered cells, like fibers in dimensions, which histologically must he termed parenchyma cells. These cells are thin- walled, unlike fibers, and have contents identical to those of paratracheal parenchyma cells. Designation of such cells as diffuse parenchyma seems unavoidable. Examples of these diffuse parenchyma cells are shown for Baccharis rosmarini folia (fig. 29, lighter-appearing cells, above and left; note similarity to paratracheal parenchyma) and Olearia pirnele oldes (fig. 30, dark-staining cells, above). According to the

of Astereac. in woods observed were tyloses No

TYLOSES

as advanced. regarded be well also might Chrysothamnus,

as genus specialized a in such particularly of parenchvnia,

minimum a to Reduction tribe. the for advanced considered

be might listed above and Psiadia Haplopappus, Baccharis,

of species the Thus, parenchyma. paratracheal abundant to

scanty from a trend hypothesized has (1937) Kribs 9). (fig.

humile in Tetramolopiurn scanty be very to said be could

parenchyma paratracheal tracheids, and vascular vessels of

abundance extreme the of token By Chrysothamnus. genus

the characterizes contrary, on the parenchyma, tracheal

para— scanty Extremely (fig. 27). rotundifolia Psiadia and

pinifolius, Haplopappus poly antha, B. B. halirnifolia, folia,

B. glorneruli 1), (fig. angustifolia Baccharis characterizes

parenchvma vasicentric abundant Relatively true. is also this

Astereae, of majority In the parenchyma. vasicentric scanty

possess typically parenchyrna.—Compositae Paratracheal

B. pilularis. and patagonica, B. 398), Brizicky & (Stern

B. halirnifolia B. glomerulifolia, concava, B. cassiniaefolia,

Bacchari,c include observed was sort this of parenchyma

diffuse which in species Other fibers. libriform of instead

cells parenchvma into mature could initials cambial form

fusi of derivatives few interpretation, unlikely an seem

not does this initials, cambial fusiform from origin, same the

have fibers and libriform cells parenchvma axial Because

novo. de parenchvnia diffuse of origin of case isolated

and an exceptional seems’ therefore, Compositae, in chyma

paren Diffuse family. the in primitive relatively as regarded

best genera the including parenchvma, axial diffuse lack

far thus examined Compositae other All family. advanced

highly a in species specialized a few in parenchyma diffuse

of occurrence to apply to expected be cannot and whole,

a as dicotyledons of study a from reached was conclusion

This derived. been have types apotracheal and paratracheal

both which from type unspecialized a primitive, as garded

best re is parenchyma diffuse Kribs of (1937), theories

1960 WOODS TROPICAL 70 No. 113 TROPICAL WOODS 71

VASCULAR RAYS Types.—In Astereae, rays may be (1) both multiseriate and uniseriate; or (2) multiseriate only. These two classes are denoted in table 1 by the fact that no figures are given for uniseriate ray height in those species which lack such rays. Relative abundance of multiseriate and uniseriate rays both proves to be a distinctive feature. For example, in all species of Baccharis, uniseriate rays are as frequent as, or only slightly less abundant than, multiseriate rays. Uniseriate rays are rare or absent in all species of Olearia but 0. panicii lata, 0. rani, 0. rani var. colorata, 0. Solandri, and 0. teretifolia. In Lepidospartum, Chrysothamnus and Gutier rezia, multiseriate rays are present exclusively, or nearly so. Uniseriate rays are more abundant than multiseriate rays in Aster spinosus and Rernya maulensis. Dimensions.—Table 1 contains data on height of multi- senate and of uniseriate rays, and width of rays. Both heights and widths of rays prove interesting systematic criteria, mostly useful at the species level, but occasionally also for generic distinctions. The markedly wide rays of Tetramolopium (fig. 10) and Grindelia (fig. 12) are distinc tive, and may be related to the herbaceous habit of these perennials. The potential value of ray width for taxonomic purposes is illustrated by comparison of pairs of species of Baccharis (fig. 2, fig. 6), Chrysothamnus (fig. 14; fig. 15) or Olearici (fig. 22; fig. 24). A number of Astereae in which uniseriate rays are scarce possess mostly uniseriate rays only a single cell in height. Examples of this phenomenon include Haplopappus acradenius and H. canus. As a generalization, one may say that such uniseriate rays are abundant in those species for which the average height of uniseriate rays is less than l00. Histology .—Variation in ray-cell shape in Astereae is between square and procumbent cells, or between square and erect cells, or both. If one accepts the often repeated dictum (e.g., Committee on Nomenclature 1957) that square cells are morphologically equivalent to erect cells, only three species of Astereae, Aster spinosus, Remya mauiensis, and Tctramoiopiztm hurnile, may be considered to have homo 72 TROPICAL WOODS 1960 cellular ray tissue. This treatment may well be the best one in terms of dicots at large, but in Compositae the most meaningful subdivision is produced by citing occurrence of crect versus procumbent, or both types of cells. Square cells (“isodiametric”) are nearly universal in Compositac. but erect cells are not. Some skepticism concerning the doc trine of morphological equivalence of square and erect cells would probably be healthy. However, using the scheme of table 1 (“Ray cells isodiametric to procumbent” and “Ray cells isocliametric to erect”) one finds some interesting dis tinctions. Baccharis, for example, characteristically has pro cumbent rays cells, and erect ray cells at wings or margins of the ray are rare or lacking, as they are in Chri’sothamnus. Olearia contains both types. Olearia Muelleri is distinctive in presence of erect cells to the near exclusion of procum bent cells. Olearia paniculata and Psiadia rotundifolia have procumbent cells exclusively. Most species of Haplopappus have both erect and procumbent ray cells, although H. Parishii and H. pinifolius are distinctive in their lack of erect cells. Species in which erect cells, similar to libriform fibers in shape, sheath the ray, may offer difficulty in that precise limits of a ray are not easy to determine. For example, the rays in Olearia argophylla (fig. 18) are probably partially sheathed by erect cells. The very narrow ray cells in some species of Chrysothamnus (fig. 14) are distinctive. Particu larly thick-walled ray cells characterize the genera Chryso tl,aninus and Gutierrezia.

PERFORATED RAY CELLS The phenomenon of perforated ray cells, that is, vessel elements formed from ray initials, has been surveyed by Chalk and Chattaway (1933). They record no instances of this phenomenon in Cornpositae, although the variety of groups in which they do report perforated ray cells suggests that occurrence in Compositae would not be unexpected. Perforated ray cells which are identical with ray cells in shape and size were found in Conyza canadensis (fig. 39) and Haplopappus laricifolius (fig. 40). An interesting aspect Fig. 17—20._-I’ig. J7, 18. Olearth argophylla, Aw-21632.——Fig. 17. I’ransecrion, showing wide, shin—walled fibers, few vessels in small groups.—tig. 18. ‘Tangential section. Note short rays, short storied hbers.—Tig. 19, 20. Olearia argophylla, FPAw-2000.—Fig. 19. Transection. Note narrower, thick—walled fibers, more numerous vessels in larger aggregations than in fig. 17—_Fig. 20. Tangential section. As compared to fig. 1 8, rays and fibers are longer. All, x 65. No. 113 TROPICAL WOODS 73 of perforated ray cells which appears to have been bypassed by Chalk and Chattaway is the nature of lateral wall pitting. In both of the instances mentioned, lateral wall pitting of perforated ray cells is like that of vessels, that is, alternate bordered pits. In Haplopappus laricifolius (fig. 40), the heli cal sculpturing of vessels is present in the perforated ray cells. Significantly, the bordered pits in these ray cells are smaller in size, and with narrower borders, than those in vessel elements. That this may be a general phenomenon of perforated ray cells is suggested by the occurrence of such pits in perforated ray cells in a genus of Hydrangeaceae, I)eutzia (Charles F. Quibell, unpublished). In the instances cited, presence of perforated ray cells appeared to be related to breakup of large multiseriate rays, a relationship noted by Chalk and Chattaway (1933).

GROWTH RINGS; RING POROSITY As the column headed “Elements distinguishing early wood in rings” in table 1 indicates, a large number of Astereae have differential distribution of elements with rela tion to growth rings, or different dimensions in some of these elements. The elements shown in this column are those which are present in early wood and contrast with those of late wood. Where wider vessels arc indicated, for example, narrow vessels and often vascular tracheids are almost always present in late wood. A list of species with vascular tracheids is provided under “VESSELS” earlier in this paper, and these are the species which have such distribution of vascular tracheids largely in relation to growth ring phenomena. Interestingly, bands of axial parenchyma, which must be termed marginal, replace fibers in early wood of some Astercae, as table 1 indicates. Examples of fairly subtle growth ring phenomena arc seen in fig. 1, 3, 16, 19, 21, and 27. More prominent growth rings are represented in fig. 5, 7, 13, and 23. Species in which “wider vessels” are specified for early wood in table 1 must be termed ring porous, or at least having a ring_porous tendency. An excellent example of conspicuous ring porosity is illustrated by Olearia virgata in fig. 23. Although a ring-porous condition, or other growth 74 TROPICAL WOODS 1960 ring phenomena, is perhaps an obligatory feature of some Astereac, acquisition of growth rings must be a more casual matter for other species. For example, of the several collec tions of Baceharis halimifolia and Olearia argophylla respec tively, some show growth rings clearly whereas others do not. STORIED STRUCTURE A surprisingly large number of Astereae show storied structure at least to some extent. The most prominent instance of storying is shown by Olearia paniculctta (fig. 26), in which most rays are storied. In most species with storied structure, all vertical elements conform to the same storied pattern. Some other species in which libriform fibers do not appear storied do show storying in the remainder of the axial portion of the xylem; this condition is doubtless caused by differential elongation of libriform fibers, obscuring the storied pattern evident in the other axial elements. Needless to say, the fusiform initials in such species are, in all likeli hood, storied. Storied structure was completely absent in a minority of the species studied. Examples of storied struc ture which are illustrated here include Baceharis angustifolia (fig. 2), B. rosmarinifolia (fig. 4), B. myrsinites (fig. 6), B. lanceolata (fig. 8), Tetra’moiopium humile (fig. 10), Chryso thamnus nauseosus ssp. conszmths (fig. 14), Olearia argo— phylla (fig. 18, 20), 0. paniculata (fig. 26), and Psiadia rotundifolia (fig. 28). The degrees of clearness in the story ing obviously vary in these examples, depending on whether fiber elongation is relatively uniform, for the most part. Species with very short fibers, such as Olearia argophylla (fig. 18) show storied structure much more clearly than species with longer fibers such as Baccharis lanceolata (fig. 8). Considered in terms of taxonomic distribution, all species of Olearia show storied structure. Similarly, the vast maj or ity of Baccharis species exhibit storied structure. Interest ingly, within a single species, some samples may show storied structure, and others non-storied structure, as in the case of Baccharis halimifolia (see table 1). Thus, it is conceivable that even some of the species in which storied structure was not observed might in some instances exhibit storying. Fig. 21-24.—Fig. 21, 22. Olearia pimeleoides.—Fig. 21. Transection, showing end of growth ring below center, patches of narrow vessels. Fig. 22. langential section. \ote oarrow multiscriare rays, rhick—walled hbers.—Fig. 23, 24. Oleciria virgata.—hg. 23. Iransection, showing marked ring porosity. Large vessels above center of photograph. patches of narrow vessels below—Fig. 24. langential section. 1\ote wide multi— senate rays, absence of uniseriare rays. All. 65. No. 113 TROPICAL WOODS 75

In view of the high degree of specialization of woods of Astereae in other respects, the abundance of storied struc ture in this tribe is not surprising. Storied structure is rare in the genus Haplopappus. The only species in which it was observed to be at all conspicuous was H. ericoides. Thus, presence or absence of storying is to some degree related to taxonomic units. Storied structure seems more infrequent among the herbs in this study: Aster spinosus, Conyza canadensis, Grindelia cuneifolia, G. stricta ssp. procumbens (fig. 12), Heterotheca grandiflora, and Solidago spathulata are non-storied. In the tribes Helenieae (Carlquist, 1959) and Cichorieae (Carlquist, 1960), where few of the species could be classified as truly woody, storying is less frequent or less conspicuous than in Astereae. This is not without many exceptions, however, and no general conclusions should he drawn in this connection.

CRYSTALS Crystals have been reported in only three genera of Corn positae: Proustia (Metcalfe and Chalk, 1950; Carlquist, 1957), Ericameria (Metcalfe and Chalk, 1950), and Olearicr (Chattaway, 1956). The “elongate or rod-like” crystals in Proustia (Mutisieae) have been figured by Metcalfe and Chalk. The occurrence of crystals in Ericameria (treated herein as Haplopappus) could not be confirmed on the basis of the species studied here (H. ericoides). However, a number of Astereae possess crystals. According to the classi fication of Chattaway (1955), these would be “elongated or rod-like” (Aster spinosus, Baccharis angustifolia, B. pilularis, Heterotheca grandiflora, Psiadia rotundifolia) or “rhom boidal, square, or diamond-shaped” (Gutierrezia micro cephala, Olearia A4uelieri). In all of these instances, crystals are confined to ray tissue. An example of the elongate crystals is illustrated here for Baccharis pilularis (fig. 32) In this species, they vary from needle-like to short (fig. 32, right); the former are grouped in packets. The “rhom boidal, square, or diamond-shaped” type is illustrated for Gutierrezia microcephala (fig. 33) and Olearia Muelleri (fig. 31). Although Olearia Muelleri was the only species in

conditions. certain

under accumulations resinous form might these of some

even and studied, Astereae the of minority a small forms

obviously group last This spathulata. Solidago and flora,

grandi Heterotheca H. pinifolius, ericoides, H. canus, pus

Haplopap canadensis, Conyza pilularis, Baccharis spinosus,

Aster species: following the in observed were compounds

resin-like of deposits appreciable No 21). (fig. pimeleoides

0. and 0. paniculata, 31), (fig. Muelleri Olearia Watsonii,

H. 40), (fig. laricifolius Haplopappus 33), cephala (fig.

micro Gutierrezia include species Such rays. in sort this of

deposits massive show species some addition, In humile. pium

and Tetrarnolo 0. teretifolia, colorata, var. 0. rani leoides,

0. pirne 0. paniculata, 0. pachyphylla, 0. nitida, Muelleri,

0. 0. lac’unosa, 0. ilicifolia, 20), 19, 18, 17, (fig. argophylla

Olearia ssp. vernonioides, H. venetus grindelioides, ssp. sus

H. squarro laricifolius, H. acradenius, Haplopappus cephala,

micro Gutierrezia teretifolius, Chrysothamnus sergiloides,

B. olata, lance B. B. halimifolia, glomerulifolia, I3acchauis

woods: following the in vessels) for (chiefly observed

was 30). condition This 21, (fig. ‘pimeleoides for Olearia

shown as or vessels, of fibers occlusion in results materials

resin-like of secretion Abundant mauiensis. Remya and

rotundifolia, Psiadia studied), species (all Olearia delioides,

ssp. grin H. squarrosus megacephalus, var. phyllocephalus

El. H. Parishii, I—I. nzartirensis, laricifolius, H. acradenius,

Haplopappus microcephala, Gutierrezia cuneifolia, Grindelia

studied), taxa (all Chrysothaninus thesioides, B. marinifolia,

B. ‘ros B. polyantha, B. patagonica, neglecta, B. inyrsinites,

B. B. lanceolata, halirnifolia, B. B. glornerulifolia, concava,

B. B. cassiniaefolia, angustifolia, Baccharis species: lowing

fol the characterizes condition This cells. parenchyma axial

and ray in of droplets form the take usually These materials.

of resin-like in deposits rich unusually are Astereae

DEPOSiTS RESINOUS

name. by cited however,

are not, which species, four in them reports (1956) away

Chatt observed, were crystals which study in present the

1960 WOODS TROPICAL 76 Vg. 25—28—_Fig. 25, 26. Olerr,a paiiiculata.__Fig. 25. Iransection. essels arc grouped into large aggregations, some of which form diagonal patterns.—---Iig. 25. Iangcntial section. Rays, as well as tracheary elements, are mostly storied-—hg. 27, 28. Psiadia rotundifolia.—Fig. 27. Transec tion. N ote prominent paratracheal parenchyma and handed paren— chvma._—Fig. 28. Fangential section. Axial parenchvma is seen at lower left All, x 65. No. 113 TROPICAL WOODS 77

DISCUSSION AND CONCLUSIONS Variation within species.—In several species, sufficient material was available to permit discussion of the nature of infraspecific variation. The most 9pectacular differences within a species were observed in Olearia argophylla. The reader may, in fact, question whether the two samples illus strated in fig. 17—18 and fig. 19—20 respectively are, in fact, correctly identified as belonging to that species. The two samples illustrated differ markedly in length and width of vessel elements and libriform fibers, degree of vessel group ing, and presence of growth rings. Comparison of dimen sions of the five collections of this species reveal that no two are alike, and that there is almost continuous variation between the two extreme collections which have been illustrated. The only qualitative difference between the two collections is presence or absence of growth rings—seem ingly a rather casual difference, if one notes that two collections of this species possess growth rings, whereas three lack them. Although the differences are interesting in that they suggest extreme variations in dimensions, there seems no compelling reason to question identification of any one of the samples. The variability exhibited by this species would certainly seem to reinforce current skepti cism (e.g., Stern and Greene, 1958) concerning the value of statistical treatment of dimensions or even the value of dimensions themselves. The four collections of Baecharis halirnifolia show differences in storying, and presence of growth rings, but they are close in respect to cellular dimen sions. Voucher specimens show that there is no question of misidentification in samples of this species. The two collec tions of Olearia ilicifolia illustrate a surprising similarity to each other not only in qualitative but also in quantitative features. There is a rather close agreement between the two collections of 0. paniculata, but not as close as that between the two collections of 0. ilicifolia. In particular, the two collections of 0. panicuicita differ in presence of growth rings and storying of rays. Quite another problem is offered by the two samples designated as Olearia rani and 0. rani var. colorata, respec

procum and erect both procumbent; mostly erect; (mostly

cells ray in Variations distinctions. offer 21) and fig. 17 iig.

(compare thickness fiber-wall and diameter fiber 24), tig.

18 and fig. length (compare in fiber Extremes earlier. lined

out ,as species various the among different are aggregations

these by formed patterns The 23. and 21, 25, 16, 19, 17,

fig. compare vessels: of aggregation greater progressively

show Olearia of species in Baccharis, As 0. pimeleoides. for

those with 0. Cunninghamii 1 for in table figures the pare

com example, For criteria. as specific usable likelihood all

are in dimensions vessel in differences extreme Olearia, In

sergiloides. B. and

13. mostly Pluimne’rae in square are cells Ray species. other

of rays in absent or are rare they whereas H. po1’antha,

and B. Plurnmerae, B. myrsinites, in lanceolata, B. present

cells are Erect distinction. of point a is shape Ray-cell

criteria. additional provide above) discussion (see width ray

and B. in thesioides) rays high exceptionally (e.g., height

Ray species. most in absent completely seems this tive;

distinc is (see above) species some in parenchyma axial of

type a diffuse of occurrence 34). The (e.g., fig. species most

35) do than (e.g., fig. sculpture helical coarser markedly

possess B. rosmarinifolia) B. patagonica, obtusifolia, B.

(B. concava, Baccharis of species Some interest. systematic

are of aggregation vessel of patterns particular and vanced,

ad more considered are vessels of aggregations Larger

genus. in the specialization of degrees to a clue provide

writer, the of interpretation in the aggregations, vessel of

in degrees Differences lanceolata). B. versus cassiniaefolia

(e.g., B. significant be may dimensions vessel Baccharis,

In above. topics histological to relation in mentioned

been have differences these of Some species. among ences

of differ for exploration material excellent provide Olearia

and Baccharis genera large difjerences.—The Species

other. each from separate varietally

than more be taxa not should two the not or whether tion

ques may one identified, correctly If width. and ray rings,

growth vessels, on sculpture helical of presence grouping,

vessel of degree in markedly differ samples two These tively.

1960 WOODS TROPICAL 78 Fig. 29—33.—Fig. 29. BaCCJ.’ariS rosmarinifolia. Transection. Thinner— walled cells (appearing lighter) are parenchvma; some of these arc dis tributed in a diffuse manner (above) —Fig. 30. Olearia pimeleoides. Transection. Dark_staining cells contain resinous materials and are nearh’ all axial parenchyma cells. In addition to rays (horizontal), note scattered axial parencbya cells, ahove.--_F’ig. 31. Olcaria Muelleri. Radial section, showing numerous shapes and sizes of prismatic crystals; crystals are embedded in resinous deposits, which appear dark—Fig. 32. Baccharis pilularis, radial section. Packets of elongate to almost square crystals may he seen (dark) —Fig. 33. Gutierrezia microcep1a1a, Carlquist 630. Radial section. Like Olearia Muelleri, G. microcepl3ala has variously-shaped crystals, some embedded in resinous materials. Fig. 29, 30, x 170. F’ig. 3l—3, X 250. No. 113 TROPICAL WOODS 79

bent frequent) may offer specific criteria, as the symbols in table 1 for these features suggest. Certainly extremes in ray width (compare fig. 22 and fig. 24) are also prominent. Storied rays distinguish 0. paniculata. Although growth rings are not a reliable species characteristic in general, the marked ring porosity of such species as 0. virgata contrasts with less prominent rings in other species. The degree of species differences offered in Olearia by crystals and resin deposits cannot be stated clearly, but some such differences certainly must exist. In other genera, too few species are included in this study to offer broad conclusions. Attention is called to differences in rays in Chrysothamnus (compare fig. 14 and fig. 15). Haplopappus Parishii and H. pinifolius are distinctive in that genus for their lack of erect cells in rays, but the most out standing differences among species in Haplopappus are offered by degrees and types of helical sculpture in vessels, and relative degrees of vessel aggregation. Generic differences and simiiarities.—The diversity of characteristics within genera leaves few which can be used to define genera. Among those which seem to offer some distinctions, however, the following can be mentioned. The genus Baccharis is notable for the relatively abundant axial parenchyma, which occurs as paratracheal parenchyma, apotracheal parenchyma, short bands, and marginal paren chyma. The two species of Grindelia both exhibit relatively wide, high rays with thin-walled cells, thin-walled gelatinous fibers, vessels in radial rows, and non-storied structure. Olearia is marked by the unanimously storied structure of woods. Tetramoloplum humile is notable for the rarity of libriform fibers, and intensive study should be done to see if this characteristic extends to other species as well. Naturally, some of these distinctions may represent evolu tion with relation to particular habits and growth forms, as species distinctions certainly must in many instances. The wood anatomy of Grindelia does represent features which are most abundant in herbs. In fact, most species of Grindelia are relatively short-lived herbs, and the wood accumulation of G. cuneifolia and 0. stricta ssp. procumbens is exceptional 80 TROPICAL WOODS 1960 in the genus. The abundance of vascular tracheids in Tetra molopium may be related, at least indirectly, to its alpine habitats, for other alpine woody composites, such as i)ubautia Menziesii (Cariquist, 195 8a) and Loricaria thuy aides (unpublished) show similar tendencies. Despite the seeming tendency of Astereae, like Helenieae (Carlquist, 1959), to evolve with relation to particular environments, and to reveal such evolution in their wood anatomy, we may compare data on wood anatomy both to the systematic arrangements within the tribe and to what data is available on chromosome numbers. One must remem ber that evolution in w;ood anatomy with references to particular habitats; arid growth forms results in heterogeneity within smaller groupings (genera) and in considerable parallelism within genera, subtribes, etc. The genera of the present study, according to Hoffmann’s (1890) systematic arrangement of Cornpositae, would fall under the following suhtribes: Solidaginac: Grindelia, Remya, Gutierrezia, Heterotheca, Solidago, Haplopappus. Asterinae: A ster, Oleciria, Tetramolopium. Conyzinae: Psiadia, Conyza. Baccharidinae: Baccharis. Presumably, Chrysothamius and Eastwoodia, not included by Hoffmann, would fall under Solidaginae. Some species of Chrysothamnus, such as C. teretifolius, bear a close resern blance in wood anatomy to certain species of Haplopappus. On grounds of gross morphology also, the two genera are sometimes difficult to distinguish. Lepidosparturn has traditionally been placed in Senecioneae. However, the writer is of the opinion that this genus actually belongs to \stereae, and is preparing an account which will detail the Fig. 34—4O.-—Fig. 34—38. Lateral walls of vessels, showing pitting and helical sculpture—Fig. 34. Baccharis angustdolia Minute pairs of hands accompany helices of pirs.—Fig. 35. Raccbaris p.#agolflca. Coarser spirals characterize vessel walls—Fig. 36. Olearia C-unving1ainii. Although spirals are absent, grooves interconnect some adjacent pit ipcrttirc.-— Fig. 37. Olearia argo phylla. Note, especially at cut edge of vessel wall, short pairs of eminences beside each pit aperture—Fig. 38. Olearia pachyphylla. Coarse spirals, which form irregular patterns at juncture of vessel elements, may be seen.—Fig. 39, 40. Perforated ray cells.—Fig. 39. Conyza caj,adenis. Perforated ray ccli, center, has bordered pits which arc smaller than those of true vessel dc— nients.—Fig 40. Haplopappus laricifo/ins. Three perforated ray cells in a radial series. The vessel—wall characteristics are evident in the fine spirals which may he seen. Fig. 34, 34, x 410. Fig 36—38, >< 410. Fig. 36—- 38, )< 500. Fig. 39, 40, X 605. No. 113 TROPICAL WOODS 81 various bases for this transfer and the nature of its relation ships within Astereae. Hoffmann’s system of classification is probably similar at least in many respects to others which could be propounded. I )espite evolution of particular species toward specialized conditions, wood anatomy tends to support Hoffmann’s sub- tribal groupings in the main. The genera of Solidaginac show a certain resemblance to each other, at at least by virtue of the diverse and sometimes relatively unspecialized woods in the genus Haplopappus. This group corresponds with the “Haplopappus alliance” of Raven et al. (1960). These authors note that although x = 9 is the basic chromo some number in this group, considerable alteration in chromosome number (e.g., n = 6, 12 in Grindelia) has occurred. The details of wood anatomy cannot be expected to parallel exactly the results from chromosome studies. Indeed, the materials studied and summarized by Raven and his collaborators consist of species mostly different from those used in this study, so that results are difficult to com pare. Nevertheless, the idea that Haplopappus represents a genus containing both primitive and advanced characteristics would receive support on the basis of the present study. Interestingly, the genera studied here which would belong to Hoffmann’s Asterinae show some specializations to a greater degree than the genera of Solidaginae, although Aster spinosus (which has n = 9 according to Raven et al.) is the least specialized. Tetrarnolopium humile, which shows such advanced xylary features, has departed from the x = 9 basic number; it has n = 7 (Cariquist, 1956). The uniform ly storied woods of Olearia, with prominent vessel aggrega tion and helical sculpture development, are all indicative of a high degree of advancement for that genus. One species each of Psiadia and Conyza do not constitute sufficient material for conclusions. Reflecting its advance ment in terms of such features as unisexual heads, Baccharis is also advanced in wood anatomy, and inclusion in a pre sumably advanced (at the end of Hoffmann’s Astereae) subtribe, Baccharidinae, would seem justified in the basis of such features as apotracheal parenchyma, storied structure, 82 TROPICAL WOODS 1960 vessel aggregation, etc. Incidentally, Baccharis still possesses the basic chromosome number for the tribe, n = 9 (Raven et al., 1960). Tendencies in Astereae.—Astereae cannot be defined as a tril)e on the basis of wood anatomy alone. This statement can be made of all of the tribes of Compositae studied thus far. Like them, however, Astereae shows certain distinctive tendencies of its own. Most prominent among these is the abundance with which various types of helical sculpture, particularly fine and coarse bands, are represented. For dis cussion of the evolutionary significance of helical sculpture in vessels, see above under “VESSELS.” Species which show minimal aggregation of vessels closely resemble vessel grouping in other tribes, but the high degree to which vessels are grouped in Astereae as a whole and the varied patterns vessel aggregation takes, are exceptional in Con positae. Presumably a high degree of vessel aggregation suggests a specialized condition, for reasons mentioned earlier. Likewise, vascular tracheids, a component of special ized woods with extremely narrow vessels, are abundant in Astereae. The relatively short vessel-element length of Astereae as a whole corresponds to a more advanced position of the tribe within Compositac than, say, Heliantheae or Mutisieae. Likewise, storied structure is exceptionally fre quent in Astereae. These conclusions, interpreting Astereae as a whole as more advancd in xylary fatures than woods of at least some other tribes, would agree with the suggestion of Raven and his collaborators (1960) that Astereae repre sents a group derived from helianthoid ancestry. Incident ally, these authors claim that Grindelia and Eastwoodia, which have been considered by various authors either close to, or members of, Heliantheae despite their traditional placement in Astereae, are actually members of A.stereae. Although the writer (1958a) compared them wtih Helian theae in a paper on woods of that tribe, the resemblance with the majority of Astereae is somewhat closer than resemblances with the majority of Heliantheae, although the choice is not very great. A third conclusion offered by Raven and his collaborators, namely, that Astereae should No. 113 TROPICAL WOODS 83

be regarded as primitively woody, would seem to be rein forced on the basis of the present study. There are no features in the wood anatomy which would suggest herbace ancestry for woody genera where a number of species were studied, such as Baccharis, Haplopappus, and Olearia. That this negative statement does not merely allow for the possibility of herbaceous ancestry should be obvious to any- one who has followed the findings of wood anatomists. Wood anatomists have compiled a tremendous quantity of data tending to show that in group after group, ancestral types must have been woody. Such interpretations are rein forced, in most cases, by the similar conclusions, based on different evidence, of taxonomists. Thus, the burden of proof appears to lie upon the worker who claims herbaceous ancestry in a group. Some weakly woody Compositae may have had herbaceous ancestry (Carlquist, 1960; Raven et al., 1960), but the evidence in Astereae, far from countering the well-established woodv-to-herbaceous trend in dicots. seems to support it.

LITERATURE Cirm CARLQUEST, S. 1956. Tetramolopium humile, in Documented chromo some numbers of plants. Madroflo 13: 206. 1957. Wood anatomy of Mutisieae (Compositae). Trop. Woods 106: 29—45. • 1958a. Wood anatomy of Heliantheae (Compjositae). Trop. Woods 108: 1—30. • 1958b. The woods and flora of the Florida Keys. Compositac. Trop. Woods 109: 1—37. 1959. Wood anatomy of Helenieae (Compositae). Trop. Woods 111: 19—39. 1960. Wood anatomy of Cichorieae (Compositae). Trop. ‘Woods 112: 65—91. CHALK, L., AND M. MARGARET CHATrAWAY. 1933. Perforated ray cells. Proc. Roy. Soc. London B 113: 89—92. CHATTAWAY, M .MARGARET. 1955. Crystals in woody tissues; Part I. Trop. Woods 102: 55—74. 1956. Crystals in woody tissues; Part 11. Trop. Woods 104: 100—124. COMMITrEE ON NOMENCLATURE. INTERNATIONAL ASSOCIATION OF Woon ANATOMISTS. 1957. International glossary of terms used in wood anatomy. Trap. Woods 107: 1—36. 84 TROPICAL WOODS 1960

I-I0FFMANN, 0. 1890. Composirae, in Engler and Prantl, Die natür lichen Pflanzenfamilien 4(5): 1—402. KEIBS, D. A. 1937. Salient lines of structural specialization in the wood parenchyma of dicotyledons. Bull. Torrey Bot. Club 64: 177—186. L.ANJOUW, J. AND F. STAFLEU. 1959. Index herbariorum. Part 1. The herbaria of the world. ed. 4, International Bureau for Plant Taxonomy and Nomenclature. Utrecht. METCALFE, C. R., AND L. CHALK. 1950. Anatomy of the dicotyledons. Clarendon Press. Oxford. MUNZ, P. A., AND D. D. Kitcx. 1959. A California flora. Univ. Calif. Press. Berkeley. RAVEN, P. H., 0. T. SOLBRIG, D. W. KYHOS, AND R. SNOW. 1960. Chromosome numbers in Compositae. I. Astereae. Amer. Jour. Bot. 47: 124—132. STERN, W. L, AND K. L. CHAMBERS. 1960. The citation of wood speci mens and herbarium vouchers in anatomical research. Taxon 9: 7—13. AND S. GREENE. 1958. Some aspects of variation in wood. Trop. Woods 108: 65—71. Tipo, 0. 1938. Comparative anatomy of the Moraceae and their presumed allies. Bot. Gaz. 100: 1—99. WEBBER, IRMA E. 1936. The woods of scierophyllous and desert shrubs and desert plants of California. Amer. Jour. Bot. 23: 181—188.