WOOD ANATOMY OF : PHYLOGENETIC AND ECOLOGICAL IMPLICATIONS

SHERWIN CARLQuIsT

Reprinted from AMERICAN JouINAL OF BOTANY Vol. 64, No. 6, July 1977 Made in the United States of A ,nerica Amer. i. Bot. 64(6): 704—713. 1977.

WOOD ANATOMY OF TREMANDRACEAE: .PHYLOGENETIC AND ECOLOGICAL IMPLICATIONS1

SHERWIN CARLQuIsT Claremont Graduate School, Pomona College, and Rancho Santa Ana Botanic Garden, Claremont. California 91711

A B S T R A C T Stems of four species of the Australian family Tremandraceae furnished sufficient material for analysis of wood anatomy. Presence of simple perforation plates on vessel elements. oc currence of libriform fibers (some septate), tendency toward vasicentric parenchyma, presence of crystalliferous axial parenchyma strands, presence of crystals singly in ray cells, and oc currence of amorphous deposits in parenchyma are all features in which Tremandraceae re semble Pittosporaceae. Wood anatomy tends to support a “rosoid” rather than a sapindalean, rutalean, or polygalalean affinity for Tremandraceae, although wood is only a preliminary indicator. By the use of numerical indices as well as such indicators as helical thickening and presence of vascular tracheids, wood of Tremandraceae is shown to be highly xeromorphic. The Tre,uantha may represent a secondary entrant into wet forests of southwestern Australia; it clearly is not relict from mesic ancestry.

THE FAMILY Tremandraceae is endemic to Aus basal stems last for several years, and these pro tralia and is especially well represented in south vided enough wood for study. In the distinctive western Australia, where the species in the present genus , P. juniperina Domin is a true study were collected. The family consists of three shrub. Although it occurs in the Stirling Range, genera: Platytheca (two species), much of which is mesic, P. juniperina grows on (about 16 species), and (two spe exposed scree slopes and can only be regarded cies). Tetratheca consists of subshrubs, branched as a xerophyte. Platytheca verticillata (Hueg.) from the base or from below soil level. The nu Baill. (= P. galioides Steetz) is a small subshrub merous innovations are mostly annual, and there with basal stems at most 5 mm in diam. It grows fore accumulate little wood; the caudex and roots on sandy areas likely to be dry in summer, and consist of much-contorted, soft, fragmented and probably do not persist for more than ap atypical xylem, and such wood was not deemed proximately five years. However, P. verticillata suitable for analysis here. The only species of does not form a knotty caudex like that of Tre Tetratheca which could provide sufficient suit mandra diffusa or the species of Tetratheca. able wood for study is an undescrihed species col The present account has been assembled be lected in the Tuttanning Reserve. This species, cause data on wood anatomy of Tremandraceae which will be described by an Australian botanist are, at present, very scanty. Solereder (1908) monographing the family, bears a superficial re contributed information based on very small semblance to T. harperi F. Muell., and the Tuttan stems, as did Heimsch (1942). Such data, while fling plants may be found annotated thus in certain useful, cannot furnish the best comparisons to herbaria. Tetratheca harperi is native to a quite wood of other families. Metcalfe and Chalk different area, north of Southern Cross, W.A. (1950) merely summarized portions of these two The two species of Tremandra occur in the most earlier works dealing with the family. Thus, the mesic part of Western Australia, the southwest present account is the first presentation of what crnmost corner. Both, however, tend to be found could be called “mature” secondary xylem in in forest openings on disturbed soil. Tremandra Tremandraceae. diffusa R. Br. has numerous wiry, sprawling stems Wood of Tremandraceae is of unusual interest from a small knotty caudex, the wood of which in that it proves rather suggestive in analysis of was unsuitable for sectioning. Tremandra stel affinities of the family. Cronquist (1968) claims ligera R. Br. could almost be called an herb be wood anatomy as indicative of a relationship be cause of limited wood accumulation, hut some tween Polygalaceae and Tremandraceae, but does not cite any data in this regard. Metcalfe and Received for publication 11 November 1976; revision Chalk (1950) claimed that anatomy was of little accepted 29 March 1977. use in establishing affinities of the family, but the This research was supported by grants from the Na data they had at hand was fragmentary. Two tional Science Foundation (GB-38901 and BMS-73- 07055-A-I). Dr. Larry DeBuhr aided in field work and main placements have been advanced for Tre in preparation of data. mandraceae. These can he very roughly re 704 July, 19771 CARLQUTST—WOOD ANATOMY OF TREMANDRACEAE 705 garded as sapindoid and rosoid, respectively, with into a strand of from 6 to 12 cells. Crystal- variants by particular phylogenists. These hy bearing cells observed in earlywood of one growth potheses are discussed in a later section of the ring, but abundant there. Amorphous resin-like paper. deposits present in various cell types in central Of equal interest is the relation of habit and portion of stem. Wood not storied. habitat to wood anatomy in Tremandraceae. In another sample (Carlquist 3770, RSA) Only one of the species studied here, Trernandra slightly different means for quantitative data were stelligera, is broad-leaved and occupies wet for obtained: vessel diameter 21 m; vessel element ests. However, even T. stelligera is found at mar length 393 /Lm; vessels per group 1.7; vessels per gins of forests rather than deep within them. The sq. mm 351; libriform fiber length 610 tm; family as a whole does not seem woody, so that multiseriate ray height 1,014 m; uniseriate ray the relationship of the wood anatomy of Tre height 275 m. rnandraceae to that of true shrubs and trees is Platytheca verticillata (Hueg.) Baill., Carl an issue of pertinence. quist 6036, RSA (Fig. 5—8). Growth rings pres ent, but not conspicuous (Fig. 5). Vessels wider MATERIALs AND METHODS—Wood samples in eanlywood, libriform fibers thicker-walled in were collected in the field in 1967 and 1974 and latewood. Mean vessel diam 25 m, mean ves prepared by drying. Samples of maximal size for sel element length 260 tm, vessels solitary or in each species were secured. Sections were pre radial chains (Fig. 5), averaging 1.7 per group. pared by means of a sliding microtome and Mean number of vessels per sq. mm 425. Per stained in safranin. Wood samples were also foration plates simple. intervascular pitting al macerated, using Jeffrey’s Fluid, and stained with ternate, pits with wide borders. Vessel-ray pit safranin. For vessel element and libriform fiber ting alternate or, more frequently, scalariform, pits dimensions, 50 measurements were obtained and quite large. Vascular tracheids present in late averaged. For other quantitative data, means wood. Imperforate elements otherwise all libri were obtained from ten measurements. Polarized form fibers with simple pits. Mean libriform fiber light was employed for locating crystals in wood length 349 m. Mean libriform fiber wall thick sections. Data is presented in textual form rather ness 3.9 m. Axial parenchyma diffuse to diffuse than tabular because of the small number of spe in-aggregates, nearly all crystalliferous. Rays cies. multiseriate and uniseriate (Fig. 6). Mean multi senate ray height 899 /Lm; uniseriates 180 m. AN ATOM ICAL DESCR1PTIONS—Platytheca juni Multiseriate rays consisting of upright, square, perina Domin, Carlquist 5688, RSA (Fig. 1—4). and procumbent cells. Uniseriate rays composed Growth rings prominent (Fig. 1), vessels wider of upright and some square cells. Ray cell walls in earlywood, libriform fibers thicker-walled in thin. Rhomboidal crystals abundant in ray cells, latewood. Mean vessel diameter 23 m, mean present singly per cell (Fig. 7, 8). Axial paren vessel element length 330 m. Vessels often chyma cells containing crystals subdivided into solitary, averaging 1.64 per group. Mean num strands of 8—14 cells, each containing a single ber of vessels per sq. mm transection 267. Per rhomboidal crystal (Fig. 7, 8). Amorphous de foration plates simple. Intervascular pitting alter posits of resin-like substances present in paren nate. Vessel-ray pitting alternate, but with pits chyma and in other cell types, especially promi much enlarged (Fig. 4). Vascular tracheids pres nent in crystal-bearing cells. Wood not storied. ent in latewood. Imperforate elements otherwise Tetratheca sp., Carlquist 5962, RSA (Fig. 9— all libriform fibers, with no borders on pits. 12). Growth rings present, not conspicuous (Fig. Mean libriform fiber length 560 m. Mean libri 9). Vessels wider in earlywood, less frequent and form fiber wall thickness 3.9 m. Some libriform narrower in latewood. Mean vessel diam 26 m; fibers septate. Axial parenchyma diffuse, scanty, mean vessel element length 302 m. Vessels soli with strands of three cells if non-crystalliferous. tary or tending to appear in tangential bands (Fig. Both multiseriate and uniseriate rays present (Fig. 9), averaging 1.52 per group. Mean number of 2). Uniseriate rays and biseriate rays abundant; vessels per sq. mm transection 257. Perforation rays three cells wide or wider are infrequent. plates simple. Intervascular pitting alternate. Multiseriate rays average 731 im in height, uni Vessel-ray pitting consisting of large laterally- senates 253 m. Multiseriate rays with upright widened alternate pits or large scalariform pits. and square cells common (Fig. 4), but some pro Vascular tracheids present in latewood. imper cumbent cells also present. Upright and square forate elements otherwise all libriform fibers, with cells present in uniseriate rays. Ray cell walls simple pits. Mean libriform fiber length 376 m. moderately thick. A few rhomboidal crystals Mean libriform fiber wall thickness 3.5 m. Axial present singly in ray cells. Most crystals present parenchyma diffuse, scanty, but also frequently in axial parenchyma (Fig. 3) and occur singly associated with vesssels. Non-crystalliferous axial in square cells (chambered crystals) that re parenchyma in strands of four or five cells. Both sult from division of an axial parenchyma initial multiseriate and uniseriate rays present (Fig. 10). 706 AMERICAN JOURNAL OF BOTANY [Vol. 64

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Fig. 1—4. Platyrheca juniperina, Cariquist 5688. 1. Transection, showing growth rings. 2. Tangential section; multiseriate rays ae narrow. 3. Transection, photographed with polarized light; crystals can be seen in axial paren chyma cells. 4. Radial section; perforation plates, lateral wall pitting of vessels, and ray cells are illustrated. Mag nifications indicated by photographs of stage micrometer, enlarged at same scale as applicable photomicrographs. Fig. 1, 2, scale above Fig. 2 (finest divisions = 10 gm). Fig. 3, 4. scale to right of Fig. 4 (divisions = 10 tim). July, 19771 CARLQUIST—WOOD ANATOMY OF TREMAN DRACEAE 707

Fig. 5—8. Platytheca veiticillata, Carlquist 6036. 5. Transection, showing vague growth rings. 6. Tangential sec tion; multiseriate rays difficult to distinguish from crystalliferous axial parenchyma. 7. Tangential section, to show density of crystals in multiseriate ray, light polarized. 8. Tangential section. illustrating shape of crystals, light po larized. Fig. 5, 6, magnification scale above Fig. 2. Fig. 7. scale to right of Fig. 4. Fig. 8, scale to right of Fig. 8 (divisions = 10 gm). 708 AMERICAN JOURN Al, OE BOEIANY [Vol. 64

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Fig. 9—12. Tetratheca sp., Cariquist 5962. 9. Transection; vessels in tangential bands. 10. Tangential section; distribution of tannins evident. 11. Tangential section to show shape of crystals, light polarized. 12. Radial sec tion, illustrating large and small crystals; light partially polarized. Magnification scale for Fig. 9. 10. above Fig. 2. Scale for Fig. II, 12, to right of Fig. 4. __

lily, 1977j CARLQUIST—WOOD ANATOMY OF TRF.MANDRACEAE 709

** ‘i;

I%J1____

Fig. 13—17. Trernandra stelligera, Carlquist 5551. 13. Transection; growth rings show apparent traumata. 14. Tangential section; cells thin-walled.—Fig. 15—17. Portions of radial sections. 15. Perforation plate traversed by strands of wall material. 16. Strands of crystals formed from subdivision of ray cells. 17. Procumbent ray cells with a single crystal each. Magnification scale for Fig. 13, 14 above Fig. 2. Scale for Fig. 15—17 to right of Fig. 8. 710 AMERICAN JOURNAL OF BOTANY [Vol. 64

Mean multiseriate ray height 2,746 m; uniseriates cheids in latewood. Vascular tracheids are pitted 298 m. Multiseriates composed of upright. like vessel elements and are the same length as square, and procumbent cells; uniseriates consist vessel elements. Imperforate elements in most of upright and some procumbent cells. Ray cell dicotyledons are much longer than the vessel ele walls thin. Rhomboidal crystals abundant in ray ments they accompany, so that on the basis of cells (Fig. 11, 12), many borne singly per cell but length alone, vascular tracheids could be distin smaller crystals present also (Fig. 12). Some guished from other imperforate elements. The axial parenchyma cells crystalliferous. Amor concept of vascular tracheids continues to be phous resin-like deposits massive in ray cells (Fig. confusing to some students of anatomy, al 9, 10, 12), present in other cell types also. though it seems readily understood by workers Tremandra stelligera R. Br., Carlquist 5551, who have examined woods containing vascular RSA (Fig. 13—17). Growth rings present (Fig. tracheids. I have attempted a detailed exposition 13), with traumatic cell formations in places be of this phenomenon (Cariquist, 1975). Heimsch tween rings. Libriform fibers narrower and thick (1942) is correct in reporting libriform fibers for er-walled in latewood. Mean vessel diam 30 m, Tremandra, but his report of “true tracheids” in mean vessel element length 288 /Lm. Vessels Tetratheca very likely refers to vascular tracheids, mostly in radial chains and multiples (Fig. 13), which were not generally distinguished from true averaging 2.2 per group. Mean number of vessels tracheids by plant anatomists at the time per sq. mm of transection 192. Perforation Heimsch’s paper was written. plates simple; a few with strands traversing the The presence of unusually large pits, both alter perforations seen (Fig. 15). Intervascular pit nate and scalariform, on vessel walls (notably ting consisting of large opposite and alternate pits. those facing rays) is of interest. These large pits Vessel-ray pits large, either alternate and laterally (Fig. 4) bespeak a lowered selective value for elongate, or scalariform (Fig. 15). Vascular tra mechanical strength, if my hypotheses (1975) in cheids present in latewood. Imperforate elements this regard are pertinent. Tremandra stelligera has otherwise all libriform fibers with simple pits. the most conspicuous scalariform pitting and lat Mean libriform fiber length 573 m. Mean libri erally-widened alternate pits (Fig. 15). Treman form fiber wall thickness 3.1 m. Axial paren dra stelligera is a sprawling species in which basal chyma mostly scanty, vasicentric, but some dif stems do not support the weight of an entire plant. fuse, consisting of three or four cells per strand, Differentiating between widened alternate pits all non-crystalliferous. Both multiseriate and that tend to extend the width of a face of a vessel uniseriate rays present (Fig. 14), about equally wall and true scalariform pits is not easy. I would, abundant, with rays wider than two cells com however, tend to believe that scalariform lateral prising the majority of multiseriates. Mean multi- wall pitting of a presumptively primitive nature, as senate ray height 1,293 m; uniseriates 253 m. in the wood of Magnoliaceae, woody Saxifraga Both multiseriate and uniseriate rays composed of ceae, etc., is not present in Tremandraceae. The upright, square and procumbent cells. Ray cell wood of Trernandraceae is in all other respects walls thin (Fig. 16, 17). Crystals restricted to highly specialized. Rather, I would speculate that ray cells, solitary in each cell. Some erect ray the scalariform (or perhaps better, pseudoscalari cells transversely subdivided into crystalliferous form) pitting of Tremandra and, to a lesser ex strands (Fig. 16). Amorphous deposits of resin- tent, other Tremandraceae represents a meta like substances present in traumatic areas (Fig. xylem-like pattern perpetuated into secondary 13) and in small amounts in other cells. Wood xylem by virtue of a lowered selective value for not storied. mechanical strength. This pitting occurs from the pith outward without change. This would repre DiscussioN—Anatomical features—The four sent the retention of a juvenilistic feature. Pre species of Tremandraceae differ in vessel element dominance of erect ray cells in Tremandraceae dimensions. These are discussed with regard to may be another. Thus a form of paedomorphosis ecological interpretations below. Variation in ves (Carlquist, 1962) may be said to occur. Those sel diameter with relation to seasonality is evident who encounter instances of paedomorphosis in all species, although most markedly in Platy should not be surprised to find it in shrubby herbs theca juniperina (Fig. 1), which could be called a (e.g., Koek-Noorman, 1976). Although the phe dry montane species. The growth rings in Tre nomenon—or better phenomena—of paedomor mandra stelligera (Fig. 13) exhibit occasional phosis in wood is most clearly seen in rosette traumata. One gains the impression from plants trees and succulents, I also included ordinary (but in the field that innovations are mostly annual somewhat woody) herbs in my 1962 description and die back during summer heat, but a few basal of paedomorphosis. portions survive, perhaps with some cambial dam The presence of scalariform lateral wall pitting age, into more than one season. may account for the report of scalariform perfora The item of greatest interest with respect to tion plates (Solereder, 1908; Metcalfe and Chalk, growth rings is the occurrence of vascular tra 1950) in Tremandraceae. 1 could not find, near July, l977J CAREQU 1ST—WOOD ANATOMY OF TREMAN DRACEAE 711

the pith or elsewhere, perforations of any but a Platytheca verticillata (Fig. 6). The report of simple type, nor could Heirnsch (1942). A few, secretory cells in stems (but not wood) of Tre slightly malformed perforation plates (Fig. 15) mandraceae (Metcalfe and Chalk, 1950) un of a non-scalariform nature were observed in Tre doubtedly refers to this kind of deposit. Iden mandra stelligera. Heimsch (1942) reports he tification of the actual chemical substances lical thickenings in vessels and tracheids (pre involved in such deposits is a prime desideratum. sumably vascular tracheids) of Tetratheca ciliata Lindi. and, more prominently, in T. efoliata F. PHYL0GENETIc RELATIONSHI ps—Wood anato Muell. my of Pittosporaceae has been thought to resemble Libriform fibers, as mentioned above, are that of Araliaceae (see Metcalfe and Chalk, present exclusively. No fiber-tracheids or true 1950). The occurrence of secretory canals in the tracheids are present. Libriform fibers are appre stem cortex of both species is probably a persua ciably longer than vessel elements in Tremandra sive subsidiary characteristic in this regard. How ceae. The ratios for mean libriform fiber length ever, Pittosporaceae show a remarkable number to mean vessel element length are as follows: of similarities to Tremandraceae with respect to Platytheca juniperina, 1.6; P. verticillata, 1.3; wood anatomy: vessels with simple perforation Tetratheca sp., 1 .2; Tremandra stelligera, 2.0. plates, alternate lateral wall pits on vessels walls, These ratios, although a little lower than for libriform fibers the only imperforate tracheary other specialized dicotyledons (2.6: Cariquist, elements (vascular tracheids aside), libriform fi 1975, p. 141), are not low enough to represent bers septate, axial parenchyma scanty paratra expressions of a primitive condition. These ratios cheal (some parenchyma strands crystalliferous in are in the range one would obtain, for example, both families), procumbent cells present in the in Asteraceae (Carlquist, 1966: ratio for all spe center of multiseriate rays (more preponderant cies averaged, 1.7). The presence of septate fi in Pittosporaceae), crystals rhomboidal and borne bers in Tremandraceae is notable. singly in ray cells (sometimes in association with Axial parenchyma in Tremandraceae ranges small crystals), and presence of amorphous de from diffuse (Platytheca) to vasicentric (Tetra posits in ray cells and elsewhere (data on Pitto theca, Tremandra). Heimsch (1942) reported sporaceae original and from Metcalfe and Chalk, that axial parenchyma was paratracheal or ab 1950). The multiseriate rays are more uniformly sent in Tremandraceae (species not cited). Both wide in Pittosporaceae than in Tremandraceae. crystalliferous and crystal-free axial parenchyma Are all of these features parallelisms? To be sure, is abundant in Platytheca (Fig. 3, 7, 8) but less many resemblances could be ascribed to similar abundant or absent in Tetratheca and Tremandra. evolutionary level (e.g., simple perforation plates, Multiseriate rays in Tremandraceae vary in presence of libriform fibers). However, a rela width from narrow, in Platytheca juniperina, to tionship between Pittosporaceae and Tremandra medium width in Tremandra stelligera (Fig. 14) ceae obviously cannot be ruled out on the basis of to wide in Tetratheca (Fig. 10). The presence of wood anatomy. procumbent cells in multiseriate rays of all spe Pittosporaceae is mentioned at this juncture cies, and in uniseriate rays of some species, is in precisely because a number of phylogenetic treat teresting and perhaps not expected in view of ments place it far from Tremandraceae. The re limited xylem accumulation, because procumbent semblances between fruits of the two families are cells tend to be more abundant in woody species considerable, and one who observes the poricidal of dicotyledons than in herb-like species (Carl anthers of Cheiranthera (Pittosporaceae) will quist, 1962). find great resemblance to the poricidal anthers of Crystal occurrence in Tremandraceae is highly Tremandraceae. Pittosporaceae has been con distinctive—rhomboidal crystals borne singly in sidered by most authors to belong to Rosales chambered axial parenchyma or in ray cells (Fig. (e.g., Wettstein, 1935; Engler, 1964; Cronquist, 3, 7, 8, [1, 17). Single large crystals plus smaller 1968), often next to Byblidaceae (which has crystals were observed in Tetratheca sp. (Fig. poricidal anthers) and Cunoniaceae. Wood of 12). Tremandra stelligera is noteworthy in that Byblidaceae (Cariquist, 1976) differs from that some erect ray cells are horizontally subdivided of Pittosporaceae in having true tracheids, diffuse into crystal-bearing strands, a feature I have ob parenchyma, narrow multiseriate rays lacking in served in Bruniaceae (unpublished data). Such procumbent cells, and in absence of crystals. subdivided crystalliferous ray cells may be more These differences are, to be sure, based on the widespread in dicotyledonous families than is at rather limited secondary xylem produced by the present evident, for few workers are detailed in more woody of the two species that comprise the their reports of modes of crystal occurrence in genus Byblis and thereby the family Byblidaceae. woods. The wood anatomy of that single species should Amorphous deposits of resin-like materials oc not be heavily stressed in comparisons. Authors cur in all Tremandraceae. These are most con who have not placed Pittosporaceae in the order spicuous in Tetratheca sp. (Fig. 9, 10, 12) and Rosales proper have followed a generally similar

disabling elements, of vessel file a of the length many are vessels Where of vessels. “redundancy”

to spread are able element vessel a bles within as be expressed could This ous, vessels. narrow

Air bub tracheids. vascular adjacent into branes numer exceptionally to have said may be 0.30

mem pit

cross cannot bubbles the air tracheid, approximately below a ratio with species cies),

a

in vascular

form embolisms if air tracheids: spe each for means using mm, sq. per vessels

as

true system the conductive of “safety” gard to by divided diameter (vessel ratio a formulates

re with

same value the have tracheids Vascular one if 1977). DeBuhr, and (Cariquist

constant

1975).

(Carlquist, xeromorphy of indicator means no by is this ratio ratio, an inverse in be to

an

certainly almost is tracheids of vascular rence mm tend sq. per of vessels and number diameter

Occur 1975).

Carlquist, 1973; (Baas, clear vessel Although of transection. sq. mm per

entirely is not significance ecological tion and vessels numerous with vessel elements, short row,

func

their a as whole, in dicotyledons tribution nar 1 formulated: the criteria to according dent

dis of their because although (1966), Carlquist evi seems of Tremaridraceae wood of morphy

and by (1936) Webber

of xeromorphy dicators

xero INTERPRETATiONS—The

ECOLOGICAL

in were considered thickenings Such (1942).

Heimsch by mentioned tracheids) vascular relationship. of natural indicators necessarily

(probably “tracheids” and vessels in thickenings are not dicotyledons, in fashion parallel in cur

helical of the occurrence by reinforced is theca oc which level, in evolutionary similarities that

of Tetra of woods nature The xeromorphic realize must anatomy wood versed in not Those

by plants. woody be survived must that affinities. validating in alone anatomy wood of

extremes of the but a species, of the habitat of the limitations stress must I “rosoid.” essentially

the measurements mean climatic not of dicator families both in and considering Pittosporaceae to

in a sensitive be remarkably to may prove index Tremandraceae allying in merit is there soning,

This values. in “mesomorphy” that than higher rea their in correct are and Thorne Hutchinson

much range dicotyledons Other 1977). Buhr, If family. I an ndomalesian Daphniphyllaceae,

Dc and 587.0 (Carlquist high as as range ceae is Daphniphyllinae, suborder, third a [n lands.

and other Penaea 45.0, than lower index an have is the Hawaiian as far as Pacific the into and

species two only in Penaeaceae, example, one into Asia ranges Pittosporum although groups,

As just of dicotyledons. other an assortment in Australian Tremandraceae—essentially and ceae,

those to low if quite compared be all would ceae Pittospora are Byblidaceae, Pittosporinae der

the Tremandra for the values However, index. subor his In Madagascar. in representatives

by this are demonstrated its habitat and habit some with is South African, that of plants group

its broad-leaved of basis the on expected have a and Roridulaceae), Myrothamnaceae, ceae,

one would that stelligera of Trernandra morphy Hydrostachya Grubbiaceae, Geissolomataceae,

meso greater The 45.0. stelligera, Tremandra (Bruniaceae, Brunineae the is suborder porales

sp., 28.6; Tetratheca 15.4; verticillata, 28.4; P. Pittos Thorne’s Within (1968). Thorne by ified

juniperina, Platytheca would be: values the here, mod much was and accepted idea This insights.

studied Tremandraceae For the 1977). Buhr, unorthodox keen although of Hutchinson’s one be

and Dc (Carlquist indicated xeromorphy of gree well may and Byblidaceae Tremandraceae with

de the the for greater this index, value the lower of Pittosporaceae grouping but the elsewhere,

The be “mesomorphy.” termed may value This placed be should two families latter The ceae.

and Viviania Stegnospermaceae, Byblidaceae, sq. mm per vessels

Tremandraceae, of Pittosporaceae, consisting

x diameter vessel length element vessel

Pittosporales, order innovation—the teresting

in species: each an contained system within obtained (1959) means Hutchinson’s

the using are incorporated, three measurements all observations. own my

which in yet index another and can formulate One Chalk (1950) and Metcalfe of data the from

9, 13). 1, 5, (Fig. high xeromorphy and ability relationship, of judging this suggestive seem not

does anatomy Wood vulner and low therefore Krameriaceae. and “redundancy” suggests alaceae

This .16). stelligera, Polyg close .10; to Tremandra sp., theca in Polygalales, Tremandraceae put

.09; .06; P. Tetra verticillata, who juniperina, theca (1969), and Takhtajan (1968) Cronquist

are (Platy low in of Tremandraceae the in treatments also seen is nerability” systems fication

for “vul The values in classi “vulnerability.” termed be from Tremandraceae far Pittosporaceae

ratio may This greater. is a of stem of tissue of ductive Placement Wettstein). Rutales as the same

the a con of portion large disabling is for much which potential the of Engler, Terebinthales the (in

the which in with wider fewer, vessels, wood a from Pittosporaceae remove some that alliances

with be contrasted can This slightly. only in ability Tremandraceae places 1935) Wettstein, 1964;

conductive total impairing unaffected, remain Engler, (e.g., Englerian the tradition However,

probably would other vessels but many vessels, 1969).

of some ability would stress conductive disable of 1968; Takhtajan. in Saxifragales Thorne,

water under formed embolisms air and narrow, of Rosiflorae the superorder in (e.g.. treatment

64 jVot.

712 OF H0TANY JOURNAL AMERICAN July, 1977] CARLQU 1ST—WOOD ANATOMY OF TREMANDRACEAE 713 a considerable portion of conductive tissue. Thus, 1975. Ecological strategies of xylem evolution. formation of vascular tracheids at the ends of University of California Press, Berkeley. growth rings in Tremandraceae gives maximal dry 1976. Wood anatomy of Byblidaceae. Bot. season “safety.” Gaz. 137: 35—38. Although Trernandra stelligera wood can be AND L DEBuHR. 1977. Wood anatomy of Penaeaceae (Myrtales): comparative, phylogenetic evaluated as the most mesomorphic of the Tre and ecological implications. Bot. i. Linn. Soc. (in mandraceae studied, it still qualifies as xeromor press). phic in terms of the criteria cited. One can hy CR0NQuIsT, A. 1968. The evolution and classification pothesize that T. stelligera and also T. diffusa are of flowering plants. Houghton Mifflin, Boston. not relicts from a long line of mesic plants. My ENGLER, A. 1964. Syllabus der Pflanzenfamilien, ed. analysis of woods in the Western Australian flora 2 [Revised by Hans Melchior.] Gebrüder Borntrae to date has uncovered primitive mesomorphic ger, Berlin-Nikolassee. wood configurations only in wet-forest species of HEIMscII, C. 1942. Comparative anatomy of the sec ondary Hibbertia (Dilleniaceae) and in some Epacrida xylem of the “Gruinales” and “Terebinthales” of Wettstein with reference to taxonomic groupings. ceae (unpublished data). To a much lesser ex Lilloa 8: 83—198. tent, Byblidaceae might be regarded as relictual HuTcHINs0N, J. 1959. The families of flowering plants. from a mesomorphic ancestry (Carlquist, 1976). Vol. I. Dicotyledons. The Clarendon Press, Oxford. The remainder of the Western Australian dicoty K0EK-N00RMAN, J. 1976. Juvenile characters in the ledonous flora consists, thus, of woods with ex wood of certain Rubiaceae with special reference to clusively simple perforation plates and other spe Rubia frutjcosa Ait. IAWA Bull. 1976/3: 38—42. cialized xylary features. The vast bulk of the METcALFE, C. R., AND L. CHALK. 1950. Anatomy of southwestern Australian flora appears to repre the dicotyledons. The Clarendon Press, Oxford. sent radiations based on at least moderately xero SoLEREDER, H. 1908. Systematic anatomy of the di- cotyledons. [Trans. by L. A. Boodle and F. E. morphic ancestors. Fritsch.] Oxford University Press, Oxford. TAKHTAJAN, A. 1969. Flowering plants. Origin and LITERATURE CITED dispersal. Oliver and Boyd, Edinburgh. BAAs, P. 1973. The wood anatomical lange in hex TH0RNE, R. F. 1968. Synopsis of a putatively phylo (Aquifoliaceae) and its ecological and phylogenetic genetic classification of the flowering plants. Aliso significance. Blumea 21: 193—258. 6(4): 57—66. CARLQuIsT, S. 1962. A theory of paedomorphosis in WasmaR, I. E. 1936. The woods of sclerophyllous and dicotyledonous woods. Phytomorphology 12: 30—45. desert shrubs and desert plants of California. Amer. 1966. Wood anatomy of Compositae: a sum J. Bot. 23: 181—188. mary, with comments on factors controlling wood WETTsTEIN, R. 1935. Handbuch der systernatischen evolution. Aliso 6(2): 25—44. Botanik, ed. 3. Franz Deuticke, Leipzig and Wien.