Wood Anatomy of Polygonaceae: Analysis of a Family with Exceptional Wood Diversity

Home , Antigonon, Antigonon leptopus, Brunnichia, Coccoloba cereifera, Dedeckera, Eriogonum alatum

Botanical Journal of the Lirtneon Society. 2003. 141. 25—51. With 59 figures

Wood anatomy of Polygonaceae: analysis of a family with exceptional wood diversity

SHERWIN CARLQUIST FLS

Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105, USA

Received May 2002; accepted for publication August 2002

Quantitative and qualitative data are presented for woods of 30 species of woody Polygonaceae. Wood features that ally Polx’gonaceae with Plumbaginaceae include nonbordered perforation plates, storeing in narrow vessels and axial parenchyma, septate or nucleate fibres, vasicentric parenchyma, pith bundles that undergo secondary growth, silica bodies, and ability to form successive cambia. These features are consistent with pairing of Plumbaginaceae and Polgonaceae as sister families. Wood features that ally Polygonaceae with Rhabdodendraceae include nonbor dered perforation plates, presence of vestured pits in vessels, presence of silica bodies and dark-staining compounds in ray cells, and ability to form successive cambia. Of the features listed above, nonbordered perforation plates and ability to form successive cambia may be symplesiomorphies basic to Caryophyllales sensu lato. The other features are more likely to be synapomorphies. Wood data thus support molecular cladograms that show the three families near the base of Caryophyllales si. Chambered crystals are common to three genera of the family and may indicate relationship. Ray histology suggests secondary woodiness in Antigonon, Atraphaxis, Bilderdyhia, Dedeckera, En ogonun-i, Hanfordia, Muehlenbechia, Polygonum, and Rumex. Other genera of the family show little or no evidence of secondary woodiness. Molecular data are needed to confirm this interpretation and to clarify the controversial sys tematic groupings within the family proposed by various authors. Vessel features of Polygonaceae (lumen diameter, element length, density. degree of grouping) show an extraordinary range from xeromorphy to mesomorphy, indi cating that wood has played a key role in ecological and habital shifts within the family; the diversity in ecology and habit are correlated with quantitative wood data. © 2003 The Linnean Society of London. Botanical Journal of the Linnean Society. 2003, 141, 25—51.

ADDITIONAL KEYWORDS: — — Caryophyllales si. chambered crystals ecological wood anatomy — helical

— thickenings Plumbaginaceae — — — — silica bodies Rhabdodendraceae successive cambia systematic anatomy — vestured pits.

INTRODUCTION naceae, Plumbaginaceae, Tamaricaceae, Frankeni aceae, Droseraceae, Nepenthaceae, Ancistrocladaceae, In Caryophyilales: evolution and systematics (Behnke Dioncophyllaceae, Simmondsiaceae, and Asteropei & Mabry, 1994), Polygonaceae (together with a sister aceae. This expanded Caryophyllaleae is termed family, Plumbaginaceae) were considered an outgroup ‘Caryophyllales si.’ here. This notably expanded defi of Caryophyllales (Rodman, 1994). The order Caryo nition invites comparison of data sets, such as wood phyllales, as defined by Cronquist & Thorne (1994) in anatomy, within the newly defined order. Wood anat the book, and accepted by the other authors, is termed omy. which frequently contains characters indicative ‘core Caryophvllales’ or Caryophyllales srnsu stricto of systematic relationship, is one of these data sets, here. Caryophyllales in this sense was a modification and the present paper represents one in a series in of the traditional Centrospermae (Eichler, 1876). A which woods of families of Caryophyllales si. are much altered definition of Caryophyllales has been compared. expressed in DNA-based cladograms (e.g. Soltis et al., Although woods of a number of genera and species 2000), in which Dilleniaceae is the basal branch from of Polygonaceae have been described, these are chiefly a dade the branches of which (preceding the core in surveys of woods of geographical regions (see Caryophyllales) include Rhabdodendraceae, Polygo Gregory, 1994). The only previous overview of wood

© 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 25—51 25 26 S. CARLQUIST anatomy of the family is in Metcalfe & Chalk’s (1950) family; (2) delineate systematic relationships; (3) Anatomy of the dicotvledon.s. That presentation. describe relationships of wood anatomy to habit and to although very useful, is necessarily very condensed. ecology. Therefore, an extended treatment of the woods of the family is desirable. Very probably, the predominantly MATERIAL AND METHODS herbaceous nature of Polygonaceae has delayed pro duction of extended treatments. The family contains The Appendix presents a list of the specimens studied. 49 genera and 1095 species according to Thorne If no institutional xylariurn is indicated cw, the wood (2000), but a large proportion of these species is her studied came from a herbarium specimen. A large set baceous. A notable exception is the subfamily Cocco of duplicate wood specimens from the U. S. National loboideae (8 genera. 230 species; more than half of Natural History Museum xylarium (USw) was incor these species belong to the genus Coceoloba). The porated into that of the Rancho Santa Ana Botanic worldwide distribution of Polygonaceae has also Garden (RSAw), and are designated with the dual deterred a survey of the woody species. Aside from xylarium citation because the USw numbers or collec Coccoloba and Triplaris, only a few species in the fam tor’s numbers were retained. In Table 1 and in the ily are genuinely arboreal, and nonarboreal species Appendix, no infrafamilial classification has been are rarely included in wood collections. Thus, wood employed. Although this may inconvenience the samples of most genera of the family are not readily reader, the fullest systematic treatments of the family obtainable from xylaria, and the specimens used for (Dammer. 1893; Roberty & Vautier, 1964) are mark the present study were assembled over a period of edly different, and interpret the phylogenetic more than a decade. The samples from secured xylaria sequence differently (based on whether cyclic or heli represent virtually all those available except for Coc cally arranged tepals are primitive). Less detailed sys coloha, which is relatively large (about 165 spp.) and tematic treatments of the family (e.g. Maekawa. 1964; which, on the basis of the present survey, is relatively Thorne, 2000) offer additional possibilities rather than uniform with respect to wood anatomy. consensus. Molecular data on the family, when avail Growth forms are diverse; among these are true able, will probably provide a more reliable infrafamil trees, lianas, shrubs of various sizes, perennials with ial classification. Nevertheless, unusual wood woody roots, and ‘woody herbs’ in which cane-like anatomical features that may reflect relationships stems of several years’ duration are innovated from among genera are cited and discussed. To synthesize the base. The genus Eriogonum alone has remarkable these data in a cladistic form would be premature and diversity, ranging from mat-like alpine shrubs with misleading, because the inframilial classification of contorted stems (E. kennedyi) to shrubs that reach the family is so controversial. treelike size on island areas (E. giganteum). The range Most wood samples were available in dried form. of wood anatomy relates to the diverse growth forms The specimens of Antigonon leptopus, Eriogonurn within the family as a whole and parallels habit and kennedyi, and Polygonum lapathifolium were pre habitat in genera such as Eriogonurn. Some Polygo served in 50% aqueous ethanol, which helps demon naceae are probably primarily woody; others are likely strate the presence of starch. Dried specimens were secondarily woody (for criteria, see discussion on pae boiled in w’atei stored in 50% ethanol, and sectioned domorphosis in Carlquist, 2001a). The two woody spe on a sliding microtome. Because of the intermixture of cies of Ru.niex studied here, R. giganteus (Hawaii) and hard and soft tissues (the result of the action of suc R. lunaria (Canary Islands) are likely examples of sec cessive cambia), rotary microtoming, using the ondary woodiness. method of Carlquist (1982), was necessary for Anti The range of wood anatomy within Polygonaceae gonon leptopus stems. Sections were stained with a also relates to ecology. I know of no other family in safranin-fast green combination. Additional sections which quantitative data on vessel features, data which of some of the species sectioned on a sliding microtome relate to mesomorphy and xeromorphy, have such an for SEM examination were left unstained, dried extreme range. between clean slides, mounted on aluminium stubs, In addition to habit and ecology, systematic distinc and sputter coated. An IS! WB-6 SEM located at the tions play a role in the great diversity of polygona Rancho Santa Ana Botanic Garden was used for exam ceous woods. The presence of silica bodies in some ination of vestured pits, crystals. and silica bodies. The genera, calcium oxalate crystals in others, and the specimen of Coccoloba t’ereifera was a twig 4 mm in diverse modes of occurrence of calcium oxalate crys diameter: other samples are of mature woody stems. tals exemplify such systematic distinctions. Macerations were prepared with Jeffrey’s Fluid and Thus, examination of wood anatomy of Polygo stained with safranin. naceae offers the opportunity to: (1) systematically The data in Table 1 pertain to the specimens and compare wood anatomy within genera and within the collections listed in the Appendix. Terminology follows

t 2008 The Licnean Society of London, Botanical Journal of the Linnean Society, 2008, 141, 2541 Thble i. wood characteristics of Polygonaceae. Abbreuiations: Ant. = Antigonon; © Atr = Atraphaxis; BiL flilderdykia; Cal. = Calligonum; Coo. = Coccoloha; to Ded. —Dedeckera; En. =Eniogonum; ym. = Gymnopodium; Ha,: =Harfordia; Mue. =Muehlenbeckii; Neo. =Neomillspaughia; Pol. =Polygonum; Sym. =Symmeria; Tn. = Tniplanis. Key to columns: 1 (VG), mean number of vessels per group; 2 (VD), mean vessel lumen diameter, 4m; 3 (VM), mean number of vessels 2mm of transection; 4 (VL), mean vessel element length, jim; 5 (VW), mean vessel wall thickness, jim; 6 (PD), mean axial diameter of intervascular pits, jim; 7 (FL), mean length of libriform fibres, Mm; 8 (Fw), mean width of libriform fibre walls, jim; 9 (PS), number of cells in axial parenchyma strands; 10 (MU) comparative ‘ predominance of multiseriate (including biseriatej and uniseriate rays; 11 (RH), ray histology (u = upright, a = square, p = procumbent, upper case indicates predominant types); 12 (MH), mean height of multiseriate (including biseriate) rays, jim; 13 (Mw), mean width of multiseriate rays, cells; 14 (UH), mean height of uniseriate rays, Mm; 15 (ST) storied elements (f = libriform fibres, nv = narrow vessel elements, p = parenchyma strands, t = vascular tracheids. v vessel elements of ordinary diameter); 16 (CS). presence of crystals or silica bodies ChF rhomboids in chambered fibres. D = druses, P = phloem ray cells. R = xylem ray cells. Rh rhomboidal crystals, Si = silica 17 (FV), C bodies); fibre/vessel element ratio; 18 (ME). mesomorphy ratio (vessel diameter x vessel element length ÷ number of vessels 2mm ). See Appendix for collection data; further information in Material and Methods

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Species VG VD VM VL VW PD FL FW PS MU RH MH MW UH ST CS FV ME

a AnL leptopus >20 (50, 663 (110) .3—7 3 252 2 3—5 M5 41 f,nv RhR,P 2.29 8.3 a Mn pungens 9.2 23 512 111 1—3 5 300 3 1—2 M=U DSP 259 2.0 73 — DP 2.70 0.5 Bil. multi/bra >20 (SW 332 (120’ 3—8 4 424 3 1—2 M>TJ LEP >5000 5.5 — f,nv D.RhR 2.45 18.1 CaL arborescens 6.8 27 140 129 2.1 5 299 2.1 2 M=U usP 266 3.6 80 nv.p SiR 2.32 27.0 Cal. coniosum 5.7 20 59 152 2.4 4 476 2.3 2 MU USP 261 2.4 81 f,nv — 2.00 5.4 C Ct En. arborescens 2.6 31 98 110 2.5 5 261 2.6 2—3 M>U usP 356 2.3 114 — SiR 2.37 56.4 C En. deserticolu 3.5 26 193 111 1—3 5 352 2.1 1—2 M=U usP 348 2.2 125 f,nv SiR 3.17 15.0 to C En. fasciculatum 3.9 15 257 158 2.2 4 365 2.6 1 M20 18 357 180 2.0 5 458 2.3 2 M>U USP 1409 3.9 101 — SiR 2.54 9.1 Neo. emarginata 2.4 41 58 269 3.6 3 834 3.0 4 M>U P 483 4.5 119 — ChF 2.35 448 0 Pol. lapathifolium >20 27 303 235 2.3 5 412 2.0 2—4 M>U DSp >1000 7.8 — f,p DR 4.76 20.9 Rumex giganteus 1.9 55 22 187 4.4 6 509 4.0 1—2 M>U DSp 1710 2.8 135 — DR 2.72 474 Rumex lurtaria 1.2 1 C 58 9 316 2.8 6 567 2.5 M=U DSp 461 2.6 257 f — 1.76 20.9 z Ruprechtia sp. 1.4 52 22 332 2.6 5 672 2.1 6 M>U P 177 2.0 95 — SiR 2.02 774 Sym. paniculata 1.5 67 40 401 2.5 3 809 2.7 5 M sP 1392 8.6 — — SiR 2.02 675 C 7}i. americana 2.0 100 10 433 5.1 6 833 1—3 5 M>U P 298 2.0 99 — ChF 1.92 4 510 Tn. ,nelanodendnon 1.6 109 7 349 4.0 6 722 2.0 5 M>1J P 298 2.0 95 — ChF 2.07 5 283 TrLput’onii 1.8 68 10 461 2.3 6 902 1.2 5 M>U P 157 2.2 75 — ChE 1.96 3 265 TrLsuninamensis 2.4 91 10 306 4.8 6 636 1.1 5 M>L P 146 2.3 73 — ChF 2.08 2 730 28 S. CARLQUIST that of the IAWA Committee on Nomenclature (1964) one can find periclinal divisions (arrows) that consti except where modified or augmented by Carlquist tute a lateral meristem (“pericyclic iueristem” of (2001a); the IAWA glossary offers careful descriptions Pfeiffer, 1926). Antigonon leptopus is cited by Pfeiffer that correlate well with wood physiology, although a (1926) as an example of successive cambia, but the more recent one exists (IAWA Committee, 1989). Ves ‘pericyclic meristems’ (lateral meristems in my earlier sel lumen diameter is used rather than outside vessel papers on Carophyllales with successive cambia) of a diameter because lumen diameter more accurately less conspicuous sort are mentioned by him in Rheurn reflects hydrologic functioning of a vessel. Where ves and Rurnex. Perhaps in Rheum and Rurnex. these mer sels are oval in transection, the diameter is based on a istems contribute to cortical expansion, since they evi average of long and short chords. Estimation of vessel dently do not lead to successive cambia. diameter and number of vessels mm4 is difficult in Apparently previously unreported are the strands those species in which vasicentric or vascular trache of intraxylary phloem at the inner edges of fascicular ids are present, because the imperforate nature of zones adjacent to the pith in Antigonon leptopus these tracheids is not evident in transections. Absence (Fig. 4, arrowed). Pfeiffer did report fibrovascular bun of a perforation plate from an element the pitting of dles with secondary growth in the cortex of Coccoloba. which is like that of a vessel can be detennined accu He also reports phloem strands in “interfascicular rately only from macerations. Estimated mean vessel areas” of Polvgonum. Neither of these phenomena diameters and vessel element lengths. indicated by were observed in the material of Coccoloba and parentheses in Table 1, are presented because marked Polygonurn in the present study. Pith bundles in which dimorphism in vessels (as indicated by diameter) cambia form, producing secondary xylem centrifugally occurs, and data were collected separately for wide and secondary phloem centripetally, are figured by and narrow vessels. An arbitrary designation for wide Dammer (1893) in Rheum. vs. narrow vessels is necessary in such woods, and highlighting the presence of this phenomenon, rather than obtaining precise quantitative data relative to it. GROWTH RINGS seems the important concern. Means are based on 25 Changes in vessel diameter can be seen within the observations per feature (note that in a species with vascular bands of Antigonon leptopus (Fig. 1). Narrow dimorphic vessels, a much larger sampling would vessels succeeded by wider vessels occur in each of the be necessary to obtain an accurate mean for vessel two vascular bands. This counters a widely held but diameter). erroneous idea that initiation of a vascular band coin The phylogenetic sequences and systematic group cides with earlywood formation in dicotyledons with ings within the family have been quite diverse (e.g. successive cambia. Dammer, 1893; Maekawa, 1964; Roberty & Vautier, In Polygonaceae with single cambia, growth rings 1964). Therefore, the data of Table 1 and the Appendix vary from clearly diffuse porous to strongly demar are arranged in alphabetical order. Although the num cated changes with season in wood histology. Few ber of species studied may seem small for a family Polygonaceae lack growth rings, with absence estimated to contain 1095 species, most of the larger recorded only in Coccoloba longifolia, C. rugosa, genera are too herbaceous to offer any secondary C. uvifero (Fig. 20) and Rumex lunaric (Fig. 45). xylem that would have a pattern mature enough to Growth rings with earlywood vessels perceptibly compare with that of true woody stems. wider than latewood vessels, but with no other appre ciable seasonal differences, were observed in RUder dykia inuitiflora (Fig. 11), Coccoloba laurifolia. RESULTS C. polvstachya, C. rotundifolia, Eriogonurn arbore scens, Gyrnnopodiurn ontigonoides, Harfordia mac SuccEssivE CAMBIA AND OTHER CAMBIAL roptera. Muehienbeekia astonii (Fig. 34), Polygonum VARIANTS lapathifoliurn, and Triplaris melanodendron. In One species of Polygonaceae,Antigoaon leptopus, is an Polvgonum lapathifolium, earlywood (Fig. 43, top), is excellent example of successive cambia (Pfeiffer. 1926) characterized by wider vessels, but the wide vessels and their products (Figs 1—4; figures are grouped at are surrounded by narrower vessels. the end of the Results). The relatively old stem studied Growth rings with vessels wider in earlywood and here shows vascular bands that in transection are narrower in latewood, but also with vessels more irregular in contour and subdivided by wide rays. Por numerous in latewood were observed in Atraph axis tions of two concentric rings of vascular tissue are pungens, Caliigonum comosum, and Eriogonum shown in Figure 1. The secondary xylem (Fig. 2) is like giganteum (Fig. 24). These features, plus occurrence that produced by pecies of Polygonaceae with single of vascular tracheids in latewood were recorded for cambia. Inside the ring of cortical sclereids (Fig. 3, Antigonon leptopus (Figs 1, 3), Dcdeckera eurekensis,

@2003 The Linnean Society of London, Botanical Journal of th. Linnean Sociei, 2008, 141, 26—61 WOOD ANATOMY OF POLYGONACEAE 29

Eriogon urn deserticola (Fig. 33), K fasciculata Tripharis americana (0.1), and T melanodendron (Fig. 32) and E. giganteurn cFig. 24). Growth rings (0.06) are representative of this tendency. Relatively with the above features, but without latewood vascu high vessel density/diameter ratios occur in dryland lar tracheids and with latewood libriform fibres nar polygonaceous shrubs with narrow vessels, many per rower and thicker-walled than those of earlywood, unit transection (Dedeckera, Eriogonurn, Harfordia. were observed in Calligonum arborescens (Fig. 16), Muehlenheckia). Although not a dryland shrub, such a Neomilispaughia emarginata (Figs 39, 41), Ruprech ratio is found in the wood of the canelike stems of tia sp., Triplaris americana (Fig. 51), T pavonii, and Polygonum lapathifoliurn. T sari nutnensis. Mean vessel element length in Polygonaceae (Table 1, column 3) shows a wide numerical range, from 105 jim in the sand dune shrublet Dedeckeru VESSELS eurekensis to 549 jim in the tropical tree Coccoloba Mean number of vessels per group (Table 1, column polystachya. This range, however, is lower than one 1) shows an exceptional range in Polygonaceae. would expect, considering that the mean vessel ele Means of 2.0 vessels per group or less occur in Cocco ment length for dicotyledons as a whole is 649 jim loba Ion gifolia, C. rugosa. Harfordia macroptera, (Metcalfe & Chalk, 1950: 1360i. Ruinex giganteus (Fig. 47), R. lunaria (Fig. 45). Vessel element length was computed separately for Ruprechtia sp., Syrnmeria paniculata, and all species the short and long vessel elements in two species of of Tripiaris except T. surinarnensis. At the other Polygonaceae with vessel dimorphism. In Antigonon extreme, vessel groupings so large that accurate leptopus, wide vessel elements have a mean length of counts and means are impossible to calculate occur in 83 jim (and are thus mostly wider than they are long — some Polygonaceae; the extensiveness of these group see above), whereas narrow vessel elements have a ings may not be evident from some photomicrographs mean length of 140 pm. In Bihderdykia rnultiflora, the because very narrow vessels resemble libriform wide vessel elements have a mean length of 90 pm. the fibres. Illustrations that show extensive vessel group narrow ones a mean length of 173 jim. ings are offered here for Antigonon leptopus (Fig. 1), Vessel wall thickness (Table 1, column 3) mostly Bilderdykia rnultiflora (Fig- 11), Muehlenbeckia asto falls between 2 and 4 p.m in Polygonaceae. Wider ves nii (Fig. 34, and Palygonurn lapathifoliurn. The mean sels tend to have thicker walls. Thus, the tropical tree number of vessels per group for a species such as genera Coc-coloba, Neornilispaughia, and Tripiaris Calliganum arhorescens (Fig. 18) is difficult to obtain have mean wall thickness greater than 3.0 pm (the because patches of very narrow latewood vessels twig specimen of Coccoloba cereifera falls below that. (which may include some vascular tracheids) may be and has narrower vessels). For species with a wide large while earlywood vessels can be solitary or in range of vessel diameter, a range of mean thicknesses small groups. is shown in Table 1. A range in vessel wall thickness is Mean vessel lumen diameter (Table 1, column 2) particularly characteristic of the genera with vessel shows an amazing range from 18 jim (Hurfordia mac dimorphism, Antigonon and Bilderdykia. roptera, Muehlenbeekia astonii: Fig. 34) to over Pit cavity diameter (measured parallel to long axis 100 jim in the tropical trees Coccoloba polvstachya, of vessel) is relatively uniform (3—5 jim) for most of C. rugosa, and Triplaris arnericana (Fig. 51). the family (Table 1, column 6j. Pits with somewhat Vessel dimorphism. in which vessel diameter tends greater diameter occur in Coccoloba, Q’,’rnnopodiurn, to fall into a bimodal pattern (although never exactly Rurnex. and Thipiaris Table 1, column 6). This so), occurs in the woody herb’ Pol-vgonu,n laputhifo applies to pit cavities of both vessel-to-vessel and ves hum (Fig. 43). More marked vessel diameter dimor sel-to-ray and vessel-to-axial parenchyma pitting. phism occurs in the lianas Antigonon leptopus (Fig. 1) Vessel pitting is alternate, and generally circular, and Bilderdykia rnultiflora (Fig. 11). The narrow ves with some tendency toward oval shapes. More elon sels inAntigonon Ieptopus (Figs 1,3) average 10 jim in gate shapes, corresponding to the term pseudoscalar lumen diameter, whereas the wider vessels average iform, were observed in vessel-to-vessel pitting in 145 jim. Antigonon leptopus, Dedeckera eurekensis, Eriogonum Vessel density (Table 1, column 2) is often thought fasciculaturn, and, to a modest extent, in Raprechtia to be approximately inversely proportion to vessel sp., Triplaris americana, T. rncianodendron. and diameter. In Fouquieriaceae. the vessel density to ves T surinamensis. Pit aperture shape is narrowly sel lumen diameter ratio is close to 2.0 for most species elliptical on vessel to vessel pits, but more widely (Carlquist. 2001b), but in Polygonaceae. one finds a elliptical in vessel to axial parenchyma or vessel to much wider range, because tropical trees have few. ray parenchyma. wide vessels and thus have low density/diameter Vestured pits have been reported in Polygonaceae ratios: Coccoloba polystachya (0.05), C. uL’ifera (0.06), for the genera Brunnichia, Muehlenbeckiu, and

Triplaris, and have been reported to be absent in Cue Muehienbeckia astonii, Neornillspaughia ernarginata, coloba (Jansen et al., 1998). In the present study. yes Polygon urn lapathifolium, Rurnex giganteus. Ruprech tured pits are figured for Atraphaxis frutescens tin sp., Symmeria paniculata, Triplaris americana, (Figs 5, 6),A. pungens (Figs 7,8), @vrnnopodium anti and T melanodendron. These are all new records for gonoides (Fig. 9), Muethenbeckia astonii (Fig. 36), the family and include all of the genera studied. Non- Ruprechtia sp. (Fig. 59), Rumex giganteus (Fig. 49’, bordered perforation plates probably characterize the Triplaris pauonii (Figs 56, 57) and T surinarnensis family However, an occasional bordered perforation (Fig. 58). \‘estured pits were also observed and photo plate can be found in a few of the species examined, as graphed with SEM but not figured in the present shown for Ei-iogonurn giganteurn (Fig. 29). paper for Bilderdykia aubertii, Coccoloba longifolia Vessel restriction patterns occur in Muehlenbeckia both vessel-to-vessel and vessel side of vessel-to-ray astonii (Fig. 34) and Poiygonurn lapathifoliurn pitting), C. polystachya, C. uvifera, Eriogonurn gigan (Fig. 43). In these examples, vessels are restricted to teurn, Polygonuin lapathifoliurn, Triplaris americana, the central portions of fascicular areas, forming strips and T melanodendron. In view of the presence of yes down the centres of fascicular areas. Thus, vessels are tured pits in Coccoloba, in contrast with the absence not, with few exceptions, in contact with ray cells. Ves reported earlier, and in view of the numerous new sel restriction patterns of this sort are probably much reports for the family offered here, many more more common in dicotyledonous woods than has at instances of vestured pit occurrence are likely to be present been noted. The phenomenon has been found in the family. recorded in seven families, which are not closely The vesturing in pits of Rurnex, Ruprechtia, and related to each other (Carlquist, 2001a: 53. Triplaris is unusually dense and extensive, spreading onto the vessel wall facing the lumen. Vesturing on simple perforation plates of Much lenbeckia was IMPERFORATE TRACHEARY ELEMENTS reported by Kucera et al. (1977). Observation by Libriform fibres with simple pits characterize all of means of SEM is the obvious technique for rendering the Polygonaceae studied. Mean length (Table 1, col vesturing clearly. However, in some families reported umn 7) ranges from 210 to 1378 m. The genera with vestures are probably droplets of secondary com the lowest mean fibre length are the shrubs Dedeckera pounds, and thus cross-checking with light micros and Eriogonurn; those with the longest are the trees copy, as done here, should be employed. Coccoloba, Gymnopodiurn, Neornillspaughia, ,Syrnme Grooves interconnecting pit apertures on vessel na, and Tniplanis. Fibre wall thickness is relatively walls have not previously been reported in vessels of uniform in the family (TabLe 1, column 8), and no Polygonaceae (Carlquist, 2001a: 96). In the present fibres indicative of reaction wood were observed in the study, such grooves were observed in Antigonon lepto species studied. pus, Bilderdyhia aubertli. Calhgonum orborescens, Judging from the presence of starch Isee below) and Coccoloba laurifolia, Eriogon urn fasciculatun?. septa in fibres of Polygonaceae, the family is probably E. kennedyi, and Polygon urn lapathifolium. characterized by living fibres (Carlquist. 2001a: 136). In the present study, helical thickenings in vessels Species in which fibres were not observed to have are reported for Atraphaxis pungens (Figs 7, 8), septa include Atraphaxis pungens, Bilderdvkia multi- Bilderdykia multiflora (narrow vessels), Eriogonum flora, Calligon urn arhorescens, Dedeckera eurehensis, giganteurn (Figs 26—29), E. heermannii (thickenings Eniogonum. arborescens, E. deserticola, E. fasciculata, slender and well spaced from each other), and Mue E. gigan team, E. heerrnannii. E. kennedyi, Rurnex hlenbeckia astonii (Fig. 36). Helical thickenings in ves giganteus, and R. lunania. A single septum per libri sels have been reported in latewood of Polygonaceae form fibre was observed in Antigonon leptopus, Cocco for vessels of Eriogonum fasciculatum and E. loba laurifolia, C. uvifera, Harfordia rnacroptera, and giganteurn (Carlquist & Hoekman, 1985). Earlier, Polygon urn lapathifoliurn; more than one recorded in Solereder (1908) listed helical thickenings in the Coccoloba longifolia, C. polystachyn, C. rotundifolia, polygonaceous genera Calligonurn, Chorizan the, and C. rugosa, Gyrnnopodiurn antinonoides, Muehien Triplaris; Record (1936) observed helical thickenings beckia astonii, Neornillspaughia ernarginata, Rupre in vessels of Coccoloba, Eriogonurn, and Ruprechtia. chtia sp., Symrnenia paniculata, Triplanis americana, Nonbordered perforation plates were recorded on T melanodendron, T pavonii. and T surinamensis vessels in the present study on wood longitudinal (about four per fibre in T suninarnensi-s). The above sections of Antigonon leptopus, Atraphaxis pungens, data do not include the septa in crystal-bearing fibres, Bilderdykia znultiflora, Calligon urn arborescens, which are described below in connection with crystal C. corn osum. Coccoloba laurifoiia, C. uvifera, Dedeck occurrence. era eurekensis, Eriogonurn giganteum (Fig. 28), Another type of imperforate tracheary element is Gytnnopodium antigonoides, Harfordia inacroptera, common in some species. Imperforate fusiform cells

pitted like vessels and formed at the termini of growth VASCULAR RAYS rings, and termed vascular tracheids (Cariquist, 2001a) are common. These are not to be confused with A wide range of ray types is found in Polygonaceae. In vasicentric tracheids, which surround vesseLs and are the species studied, uniseriate rays are present exclu best known in Quercus, although they occur in many sively or are predominant in Antigonon leptopus other dicotyledons (Carlquist, 2001a). Vascular trach (Fig. 2), all species of Coccoloba such as C. uvifera eids must be identified in macerations, because in (Fig. 21), Gvmnopodium antigonoides, and Harfordia sections, perforation plates are often missing from macroptera (Table 1, column 10). Multiseriate rays what are probably very narrow vessels. Vascular tra (including biseriate rays) are about as common as cheids were observed in Antigonon leptopus. Dedeck uniseriate rays in Atraphaxis pungens, Calligonum era eurekensis, Eriogonum arborescens, E. deserticola, arborescens (Figs 17, 19), Eriogonum deserticola E. fasciculatum, E. giganteum, E. heermannii, and (Fig. 30), E. giganteum (Fig. 25) and other species of K kennedyi. Helical thickenings were observed in the Friogonum, and Rumex lunaria (Fig. 46). Multiseriate vascular tracheids of F. kennedyi. rays were observed to be more common than uni senate rays in Bilderdykia multi/lore (Fig. 12), Calligon ant comosum, Coecoloba rugosa, Dedeckera AXIAL PARENCHYMA eurekensis, Eriogonum arborescens, Muehienbeckia Throughout Polygonaceae. axial parenchyina occurs astonii (Fig. 35), Neomillspaugh.ia emargin eta as scanty paratracheal or vasicentric. In wood tran (Fig. 40), Polygonum lapathifolium (Fig. 44), Rumex verse sections, axial parenchyma occurs in the form of giganteus (Fig. 48), Ruprechtia sp., Triplaris ameri a few cells in contact with vessels, or scattered among cana (Fig. 52), and the other species of Triplaris. Sym larger groups of vessels in contact with each other; no meria paniculata is the only species observed in which apotracheal parenchyma was observed. Axial paren uniseriate rays are absent or nearly so (Table 1, chyma is scarce in some species, such as Atraphaxis column 10). pungens. A nonsubdivided axial parenchyma cell can Ray histology in Polygonaceae is diverse. Using the be mistaken for a libriform fibre unless one notices the ray types of Kribs (1935) and Carlquist (2001a) and larger pits characteristic of axial parenchvma; also, the data on wood histology (Table 1, columns 10 and axial parenchyma cells tend to have thinner walls 11), the following types can be designated for species than libriform fibres in any given species. in the family. Homogeneous Type I occurs in Anti Strands of axial parenchyma (Table 1, column 9) gonon leptopus (Fig. 2), Calligonum cornosum, most consist of one, occasionally two cells in Atraphaxis Coccoloba species (such as C. uvifera, Fig. 211, En pungens, Bilderdykia multi/lore, Dedeckera eureken ogonum arborescens, F. deserticola (Fig. 30), Neomill sis, Eriogonum (all species except F. arborescens), spaughie emargineta (Fig. 40), Ruprechtia sp. and all Muehlenbeckie astonii, and both species of Rumex. species of Triplaris (see Fig. 52). Homogeneous Type 2 Strands of two cells were recorded in Calligonum occurs in Symmenia paniculata. Homogeneous Type (both species) and in Harfordia macroptera. Strands of III characterizes Coccoloba longifolia, C’. polystachya, two to four cells characterize Antigonon leplopus, Cue and C. rugosa. Heterogeneous ray types are less com coloba (all species), and Eriogonum arborescens. mon. Heterogeneous Type JIB occurs in Calligonurn Strands of five cells were observed in Symmeria pan arborescens (Fig. 17), Coccoloba rotundifolia, and iculata and Triplaris (all species). The number of cells Eniogonuin spp. (e.g. F. giganteum, Fig. 25). Paedo per strand parallels, for many species, the length of morphic Type I characterizes Atraphaxis pungens, fusiform cambial initials. as indicated by vessel ele Bilderdykia multiflora (Fig. 12). Coccoloha cereifera, ment length (Table 1, column 4). Dedeckera eurekensis, Eriogonum fasciculatum, There are concentric bands of parenchyma, usually F. heermannii, Muehienbeckia astonii (Fig. 35), two cells wide. intercalated into the fibrous woody Polygonum lapathifoliuni (Fig. 44), Rumex giganteus cylinder of Atraphaxis pungens. These may be refer (Figs 48), and R. lunaria (Fig. 46). The rare Paedo able to a growth ring phenomenon, such as terminal morphic Type III occurs in Harfordia macroptera. The parenchyma. stems studied for F. kennedyi, although mature, Another unusual axial parenchyma distribution, proved entirely rayless, which is a new family record not figured here, was observed in the stem bases of the for this condition. rosette perennials Eriogonum alatum Ton. (Jones 8- The height of multiseriate rays (Table 1, column 12) W-1910, POM) and E. longifolium Nutt. (McVaugh is greatest in the two lianoid species studies, Anti 7529, RSA). These two species have pervasive axial gonon leptopus (Fig. 2. extreme left) and Bilderdykia parenchyrna — parenchyma that substitutes for libri multi/lore (Fig. 12). The nonlianoid species Polygonum form fibres, which occur only near the periphery of the lapathifolium (Fig. 44) also has tall rays. In the major stems in these two species. ity of Polygonaceae, multiseriate ray height averages

between 177 jim (Ruprechtia sp.) and 461 jim (Rurnex vessels and axial parenchyma strands associated with lunaria, Fig. 46). vessels are storeyed, as shown for Calligonurn arbore Width of multiseriate rays (Table 1. column 13) is sceris (Fig. 19). Storeyed narrow vessels and associ close to two cells for most Polygonaceae Figs 21. 51, ated axial parenchyma strands were recorded for 52). Significantly wider rays occur in Antigonon lepto Antigonon leptopus, Dedeckera eurekensis, Eniogon urn pus (Fig. 2), Bilderdykia rnultiflora (Figs 12, 14), Cal deserticola, E. heerrnannii, G-ymnnopodiurn anti ligonurn arborescens (Figs 17, 19), Muehlenbeckia gonoides, and Polygon urn lapathifoliurn. Where vascu astonii (Fig. 35), Polygon urn lapathifoliurn (Fig. 44), lar tracheids are present, they occur with narrow Rurnex giganteus (Fig. 48), R. lunaria (Fig. 46, and vessels and conform to the same storying patterns as Syinmeria. pan iculata. narrow vessels. Probably. storeyed cambia and sto The height of uniseriace rays (Table 1, column 14) reyed sieve-tube elements are more widespread in ranges from 41 jim in Antigonon leptopus to 257 pm in Polygonaceae than are storeyed secondary xylem cells. B. lunaria. Although this range seems considerable, In Coccoloba, lack of narrow vessels, combined with 1,3 of the 32 species studied are notably short in unis elongation of fibres (F/V ratio about 2.0 in this genus) eriate ray height, with means between 95 and 105 jim. would minimize storeyed structure in wood. Ray cell wall thickness of more than 2 jim was recorded for Atraphaxis pungens, Bilderdykia multi flora (Fig. 14), Calligonurn arborescens (Fig. 19), En TYLOSES ogonurn deserticola, E. fasciculaturn, E. heerrnannii, Tyloses were observed in Triplaris americana (Fig. 51) Muehlenbeekia astonii (Figs 37, 38), Neornillspaughia and T surinarnensis. These tyloses have thin but ernarginata (Fig. 42), and Polygon urn lapathifoliurn. lignified walls. Ray cell wall thickness between 1 and 2 am character izes the remaining species. Ray cells were observed to have lignified secondary walls, with few exceptions. SILICA BODIES AND CRYSTALS The druse-containing cells in rays of Bilderdyhia mul Polygonaceae are unusual in having both silica bodies tiflora (Fig. 14) have thin nonlignifled walls. and calcium oxalate crystals in wood cells, but in no Tangentially orientated walls in procumbent ray species, except for Gvrnnopodium antigonoides, do cells bear numerous pits, at least some of which are these two occur together (Table 1. column 16). Silica bordered, as seen in sectional view (Fig. 22j. At least bodies were observed only in ray cells in Calligonurn a few bordered pits on tangential walls of ray cells arborescens, C. coin osum. Eriogon urn arborescens, were observed in Atraph axis pungans, Calligonum E. deserticola (Fig. 31), E. heerrnannii, Gyrnnopodiurn arhorescens, Coccoloba laurifolia, C. poh’stachya, antigonoides ‘Fig. 10, Muehlenbeckia astonii C. rotundifolia, Dedeckera eurekensis, Eriogonum (Fig. 38), and Ruprechtia sp. The silica bodies of most arborescens, E. deserticola. E. fasciculatum, Gym nop species, as seen with SEM, tend to have the form of odium antigonoides, 1-Jarfordia rnaeroptera, Muehlen spheroids with irregular surfaces (Figs 10, 31), beckia astonii, Neoznillspaughia ernarginata, whereas those of Muehlenbeckia astonii bear promi Polygonurn lapathifoliurn, Rurnexgiganteus, and Syrn nent protuberances (Fig. 38). Silica bodies may be rneria paniculata. Bordered pits on ray cells of dicot more common than the listing in Table 1 indicates yledonous woods are common (see Carlquist, 2001a: because ray cells in many species of the family are 213, 221—223). Such bordered pits have been reported filled, or nearly so, with dark-staining amorphous infrequently because most workers view the pits in deposits that tend to obscure silica bodies. face view, when the borders are difficult to see, Calcium oxalate druses were observed in the sec whereas in sectional views of pits, the borders are ondary phloem of Atraphaxis purLgens, although they clearly evident. are absent in the wood (Table 1, column 16). In dicot yledons at large, calcium oxalate crystals tend to occur more commonly in pith, phloem, and cortex than in STOREYED STRUCTURES secondar xylem. In rays of secondary xylem. druses Storeyed structures are relatively common in Polygo were seen in Bilderdykia rnultiflora (Figs 14, 15) and naceae (Table 1, column 15), but not as conspicuously Rurnex giganteus (Fig. SO). In Bilderdykia mnultiflora, as in woods of some dicotyledonous families. Many druses and rhomboidal crystals occur in thin-walled workers look for storeyed libriform fibres and rays; a idioblastic cells larger than ray cells lacking crystals. few instances of storeyed libriform fibres can be cited whereas in Rurnex giganteus, druses occur in cells in Polygonaceae: Bilderdykia rnultiflora (inconspicu identical with crystal-free ray cells. ous storeyed structure in Fig. 12). Polygon urn lapathi Rhomboidal crystals occur in three modes: in ray foliurn (Fig. 44, especially at right), and Rurnex cells (usually singly); in nonseptate libriform fibres luna.nia (Fig. 46, throughout). More commonly, narrow (numerous crystals of various sizes per fibre); and as

‘chambered crystals’, which are idioblastic libriform rence of a group of crvstalliferous fibres) and in all four fibres, with many septa and with a (usually) single of the species of Triplaris studied. These crystallifer rhomboidal crystal in each of the cells formed by sep ous fibres occur in concentric bands that alternate tation. Rhomboidal crystals, usually one per cell, were with bands of noncrvstalliferous fibres. The bands are recorded for idioblastic ray cells in Bulderdykia multi- not precisely defined: there are some scattered flora, in which druses occur in other idioblastic ray crystalliferous fibres within the hands of noncrystal cells. liferous fibres. Rhomboidal crystals of various sizes (grading into crystal sand) occur in nonseptate fibres of Harfordia ni acroptera. AMORPHOUS DEPOSITS Chambered crystals exhibit a range of forms. The Woods of Polygonaceae characteristically bear depos strands of chambered crystals in Polygonaceae seem its of dark-staining materials. These are not common to be variations of septate fibres. This is suggested in ray cells, and are evident here in Figures 1, 12, 17, most clearly in the radial sections of Coccoloba 19, 20, 21, 24, 25, 30, 35, 40, 44—48, 52 and 54. The rotundifolia (Fig. 22) and C. rugosa (Fig. 23). In characteristic mode of deposition of these compounds C. rotundifolia. the fibres are nearly as long as crystal- is seen in Figure 22 (bottom). In lQeomillspaughia, the free fibres, but septa are composed of primary wall axial crystal-bearing strands (modified crstalliferous material only. This is also true in the SEM view of fibres?) bear some crystal-free cells that contain dark- Triplaris americana (Fig. 53; some septa probably lost staining deposits (Fig. 42). Dark-staining deposits in sectiomng). Crystalliferous fibres are also seen for were observed in at least some libriform fibres in Ca! this species with light microscopy in a radial section ligonutn arborescens, C. laurifolia, C. rotundifolia, (Fig. 541 and in a transection (Fig. 55). In C. rugosa C. rugosa. C. uvifera (Figs 20, 21), Eriogonum fascicu (Fig. 23), the septa between the crystals are thicker, latum. F. giganteum, Gvznnopodium antigonoides, with lignified walls, more like those of a strand of axial Harfordia macroptera, Muelzlenbeckia astonii, Ruinex parenchyma (note mirror-image crystal pairs at top of giganteus, and R. lunaria. Fig. 3). In some crystalliferous fibres of Triplaris, Dark-staining deposits were seen in axial paren chambered crystals may occur in part of a given fibre, chyma in Coceoloba uvifera, Dedeckera eurekensis, whereas the remainder of the fibre may have one or Gymnopodium antigonoides, and Symineria panicu two septa and lack crystals (Fig. 54). lata; these deposits are to be expected in axial paren All species of Coccoloba have crystals except for chyma of other Polygonaceae. C. cereifera, in which a reLatively thin stem from a her barium specimen was studied. Cr stalliferous fibres may therefore not occur in the earliest secondary STARCH xylem of a stem of Coccoloba. All species of Triplaris Because lihriform fibres are septate in many species of studied have chambered crystals in fibres. Polygonaceae, one can use the term ‘living fibres’ for The crystals of Neon?illspaughia emarginata have them: septate fibres are indicative of prolonged fibre been regarded as present in axial parenchyma by Met longevity. This designation is underlined by the pres calfe & Chalk (1950), but I regard these strands as ence of starch, which was observed in libriform fibres homologous to the fibres containing chambered crys of Antigonon leptopus, Eriogonum arborescens, and tals in Coccoloba and Triplaris. The strands of rhom F. ken nedyi. The wood samples studied for these three boidal crystals in Neornillspaughia are very similar in species were taken from living specimens and were morphological details to those of Coccoloba and preserved in 50% aqueous ethanol, a method that Triplaris, differing only in that the strands end in cells tends to preserve starch. Very likely, starch occurs in that are somewhat rounded rather than pointed. libriform fibres of many other Polygonaceae, and is to Moreover, no diffuse parenchyma has been reported be expected in axial parenchyma of at least some for Polygonaceae, so the origin of the crystaLliferous Polygonaceae. strands seems more likeLy from fibres than from inter polation of diffuse strands of crystal-bearing paren chyma. DISCUSSION AND CONCLUSIONS Metcalfe & Chalk (19501 note that the crystallifer ous fibres of Triplaris surinamensis tend to occur in SYSTEMATIC AND PHYLOGENETIC RELATIONSHIPS bands that are reminiscent of axial parenchyma. The In a series of recent molecular-based phylogenies that crystalliferous fibres of Triplaris are clearly not axial include or are restricted to Caryophllales, Polgo parenchyma. but there is a nonrandom distribution of naceae and Plumbaginaceae appear as sister families the crystalliferous fibres in some species. This was (Downie & Palmer, 1994; Manhart & Rettig, 1994; observed in C. rotu.ndifolia (Fig. 22: note the occur- Williams eta!., 1994; Downie ci al., 1997; Soltis eta!.,

Figures 1—4. Stem sections of Antigonon leptopus including wood. Fig. 1. Transection of stem, cortex above; two vascu’ar bands shown. Fig. 2. Tangential longitudinal section; wide, tall rays at extreme right and left. Fig. 3. Portion of stem section showing cortical sclereids (topi, secondary xylem and phloem below), and tangential lateral meristem divisions in cortex tarrows). Fig. 4. Transection of pith of old stem, showing intraxylary phloem. Scale bars: Figs 1. 2 = 50 4m; 3, 4 20 jIm.

C 2008 The Linnemn Society of London, Botanical Joiniai4th. Linnean Society, 2003, 141, 25—51 WOOD ANATOMY OF POLYGONACEAE 35

Figures 5—10. SEMs of details from wood of Polygonaceae. Figs 5. 6. Atrupho..xis frutesccns, vestured pits from tangential section. Fig. 5. Inside surface of vessel. Fig. 6 External surface of vessel. Figs 7. 8. Atraphaxis pungcns, inside surface of vessels. Fig. 7. Prominent helical thickenings on latewood vessel. Fig. 8. \‘estured pits and helical thickenings from vessel. Figs 9, 10. Gvniriopodia,n antigonoi-des. portions of tangential sections. Fig. 9. Pits as seen from external side of vessel, showing vestigial vesturing. Fig. 10. Silica bodies in ray cell. Scale bars = 5 urn.

Figures 11—15. Wood sections of Bilderdykia rnuuifloro. Fig. 11. Transection; earl wood in upper half of photograph. Fig. 12. Tangential section, shong tall rays. Fig. 13. SEM of vessel wall (vertical axis horizontafl, showing grooves interconnecting many pairs of pit apertures. Fig. 14. Tangential section; a ray at left. and another at right contain thin walled druse-containing idioblasts. Fig. 15. SEM of druse from ray cell of tangential section; druse fractured by sectioning. Scale bars: Figs 11, 12 = 50 Im; 13, 15 = SMm; 14 = 20 pm.

C 2003 The Linnean Society of London, Botanicat Journal of thu Lbvwan Society, 2003, 141, 25—51 WOOD ANATOMY OF POLYGONACEAE 37

Figures 16—19. Wood sections of Calligori urn arborescens. Fig. 16. Transection, ring porous, showing growth ring; earlywood in top 2/5 of photograph. Fig. 17. Tangential section; rays are relatively short and wide. Fig. 18. Transection to show margin between latowood and eadywood. Fig. 19. Tangential section; narrow vessels are storied (centre, top to bottom). Scale bars: Figs 16, 17 = 50 tm; 18. 19 = 20 1m.

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Figures 20—23. Wood sections of Coceoloba. Figs 20, 21. C. uvifera. Fig. 20. Transection; diffuse porous; dark-staining compounds fill many cells. Fig. 21. Tangential section; most rays are uniseriate or biseriate. Fig. 22. C. rotundifolia. Radial section to show crystalliferous fibres (more than oae crystal between some septa); below, ray cells containing dark-staining compounds. Fig. 23. C. rugosu. Radial section to show septate fibre centre) and, to left of centre, a crvstalliferous fibre in which relatively thick. lignified walls separate the chambered crystals. Scale bars: Figs 20. 21 = 50 jim: 22 20 jim; 23 = 10 jim.

C 2003 The l4rniean Society of briáon, Butanic.’& JournaL of the Linnean Society, 2003, 141, 25—51 WOOD ANATOMY OF POLYGONACEAE 39

Figures 24—29. Wood sections of Eriogonurn gigonteum. Fig. 24. Transection; fluctuation in vessel diameter is not typical ring porous, but is related to differences in moisture availability within and between years. Fig. 25. Tangential section; most rays are short. biseriate or uniseriate. Figs 26—29. SEMs of interior of vessel wall from radial section. Fig. 26. Sparse helical thickenings from earlywood vessel. Fig. 27. Densely placed helical thickenings from latewood. Fig. 28. Portion of nonbordered perforation plate. Fig. 29. Portion of bordered perforation plate; helical thickenings on vessel wall below the of paired rims the perforation plate. Scale bars; Figs 24, 25, scale bars 50 tm; Figs 26—29, scale bars = 5 m.

Figures 30—33. Wood sections of Eriogorzurn, Figs 30, 31. E. deserticola. Fig. 30. Tangentia’ section. Dark-staining mate- na] present in most ray cells. Fig. 31. Silica bodies in two ray ce]ls from tangential section. Fig. 32. E. fa.sciculatum. Tangential section: earlvwood in upper half of photograph. Fig. 33. E. heermannii. Transection, to show strongly marked fluctuation in vessel diameter, corresponding to seasonal moisture availability Scale bars: Figs 30, 33 = 50 $Im; 31 5 lim; 32 20 Am.

WOOD ANATOMY OF POLYGONACEAE 41

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4- a P.S. t U’. -‘ 0 a 2-I “I, e e 1\ b fr 4W ,.‘ai36:. a. Figures 34—38. Wood sections of Much lenbeckia astonii. Fig. 34. Transection; vessels restricted to central portions of fascicular areas. Fig. 35. Tangential section: irregular storeying evident. Fig 36. SEM photograph of inner surface of vessel from tangential section showing helical thickenings and vestured pits. Figs 37. 38. SEM photographs of ray cells from tangential section, to show silica bodies. Fig. 37. Portion of silica body; protuberances present on silica body surface. Fig. 38. Small silica bodies and deposits. Scale bars: Figs 34. 35 = 50 jim: 36—38 5 Urn.

Figures 39—42. Wood sections of Neornillspaughia emarginata. Fig. 39. Transection; many vessels in radial multiples. Fig. 40. Tangential section; rays are uniseriate to triseriate. Fig. 41. Transection. Scattered among the empty libriform fibres are fibres containing chambered crystals. Fig. 42. Radial section. showing longisection of file of chambered crystals (right of centre; portions of other files at top); all ray cells arc procumbent. Scale bars: Figs 39,40 50 jim; 41,42 = 20 jim.

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Figures 43—46. Wood sections of Polygonaceae. Figs 43. 44. Polygonum lapathifoliurn. Fig. 43. Transection; vessel restric tion pattern clearly evident. Fig. 44. Tangential section; storying of fibres and vessels common, Figs 45, 46. Rumex lunoria. Fig. 45. Transection. Most vessels are solitary. Fig. 46. Tangential section; storeying evident in narrow vessels and libriform fibres. Scale bars = 50 im.

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Figures 51—55. Wood sections of Trip/erie. Figs 51, 52. T americana. Fig. 51. Transection; growth rings present; vessels in radial multiples; tyloses in vessels at bottom. Fig. 52. Tangential section; most rays are biseriate. Fig. 53. T rnplanodendron. SEM of radial section; chambered rhomboidal crystals in fibre at left, a single septum and pits visible in fibre at right. Figs 54,55. T surinamensis. Fig. 54. Radial section, showing septate fibres; some fibres are septate without crystals, some are septate and have parts with crystals, parts without them; procumbent ray cells at bottom. Fig- 55. Transection; near centre, crystals in septate fibres (grey areas surrounding crystals are septa behind crystals). Scale bars: Figs 51, 52 = 50 pm; 53 = 5 pm; 54 = 20 pm; 55 10 pm.

2008, Sockty, 141, of 2541 Linrt.an the Journal oP Botanjeal Society London. Linnean The 02008

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2000). This treatment confirms the cladistic work of onset of successive cambial activity may be delayed Rodman (1994) based on macromorphology. One considerably; this is also true in Basellaceae should note that the groupings of families of Caryo (Carlquist, 1999c). Thus, presence of successive cam phyllales other than Polygonaceae and Plumbagi bia could be a symplesiomorphy in Caryophyllales (at naceae are not congruent in all of the abovementioned least Caryophyllales s.s.), and in the genera or species cladograms, although there are many points of simi of that group in which successive cambia have never larity. Also, the data from molecular works resulted in been observed, onset of successive cambia might be creation of a broader entity, termed Carvophyllaks a?. delayed indefinitaly or the genetic information for here, whereas Rodman (1994) and earlier workers their formation may be lost. This explanation would be dealt with Caryophyllales sn, a group that to a large more parsimonious than a hypothesis that successive extent coincides with Centrospermae, which had cambia originated independently in each of the carvo stood, with inclusion and exclusion of particular fain phyllalean clades in which both normal and successive ilies, since Eichler (1876) circumscribed it. cambia, or only successive cambia, are present. This Is wood anatomy consistent with the pairing of may appeal to some as counterintuitive, because some Polygonaceae and Plumbaginaceae? Character states large families of Caryophyllales lack successive cam shared by the two families (but not widespread in bia (Cactaceae, Portulacaceae), and successive cambia dicotyledons) are numerous and include vessel restric do not occur in most clades of dicotyledons. The reten tion patterns, nonbordered perforation plates, septate tion of successive cambia in roots of Caryophyllaceae or nucleate libriform fibres. vasicentric axial paren Pfeiffer. 1926; Carlquist, 1995) is also suggestive, chyma, presence of silica bodies, storeying (at least because Caryophyllaceace is commonly placed basally in narrow vessels in some species), successive cambia within Caryophyllales si. (e.g. Soltis et al., 2000). (Antigonon in Polygonaeeae; Aegialitis in Plumbagi The presence of nonbordered perforation plates in naceae), and pith bundles with secondary growth Caryophyllales is pervasive (see Carlquist, 1999b, in some genera of each family (Carlquist & Boggs, 2000). Although the entirety of Caryophyllales has not 1996). Of these features, vasicentric axial paren been surveyed with respect to this feature, only a few chyma and presence of silica bodies may represent bordered perforation plates have been observed (some synapomorphies. Cactaceae, Carlquist, unpublished; Eriogonam gigan In the cladogram of Soltis at at. (2000), Rhab team, Fig. 29, this paper; Stegnosperma, Horak, 1981a dodendraceae were placed basal to the branch of but not Cadquist, 1999a). In addition to the wide Caryophyllales si. that includes Polygonaceae and spread occurrence of nonbordered perforation plates Plumbaginaceae. [Note: in the last sentence of in Caryophyllales. their occurrrence in genera placed Carlquist (2001c), the wording indicating that Rhab more basally in Caryophyllales si. by Rodman (19941 dodendraceae should be included in Carvophyllaceae and Soltis et at. (2000) is suggestive that they are a is an error; inclusion in Caryophyllales was intended.] symplesiomorphy in Caryophyllales si. They occur in Features that are shared by Rhabdodendraceae and numerous families of Caryophyllales (see Carlquist, Polygonaceae include ability to form successive cam 2000; they are also present in Tamaricaceae and bia (some species only), presence of silica bodies, pres Plumbaginaceae: Carlquist, unpublished), and are ence of vestured pits in vessels, and presence of omitted from the cladograms of Soltis et ai. (2000). massive deposits of dark-staining compounds, espe At the intrafamilial level within Polygonaceae, some cially in rays (Cariquist. 2001c). Silica bodies occur in features parallel taxonomic distribution and relation Plumbaginaceae as well as in Caryophyllales si. ships proposed by earlier authors. Dammer (1893) (Ancistrocladaceae and Dioncophyllaceae) and might includes Coccoioba and Tripiaris in the same subfam be a symplesiornorph The presence of vestured pits ily (admittedly in different tribes). Closeness of these in Polygonaceae in Polygonaceae and Rhabdoden two genera (along with Neonziiispaughia) is suggested draceae, on the contrary, seems better interpreted as a by the presence of chambered crystals in septate fibres synapomorphy, because the feature is absent else (Table 1, column 16). Other genera without cham where in Caryophyllales (either as. or si.). bered crystals (Antigonon, Muehienbeckia, Huprech The presence of successive cambia in one or more tie, and Symmeria) are also placed by Dammer (1893) species of a family characterizes Caryophyllales s.s. in the subfamily Coccoloboideae. Maekawa (1964) (except for Achatocarpaceae, Cactaceae. Didieriaceae. stresses closeness of coccoloboids and triplaroids. and Portulacaceae). The absence of successive cambia The occurrence of silica in ray cells and the occur in some Phytolaccaceae (Carlquist. 2000), most Plum rence of calcium oxalate crystals is almost mutually baginaceae. and some Rhabdodendraceae is curious. exclusive in the species studied: only one genus (Gym However, the successive cambia of Stegrtosperntn riapodiurn was observed to have both. The genera (Carlquist, 1999a) may provide an explanation. As with silica bodies — Caiiigonu.m, Eriogonuin. Muehien shown in that genus Horak by (1981a, 1981b), the beckia, Ruprechtia, and Symnieria — are assigned to a

number of distinct subfamilies and tribes both by upright cells. Multiseriate rays in which upright and! Dammer 1893) and by Robert & Vautier (1964). or square cells are more common than procumbent Silica presence is therefore unlikely to parallel taxo cells can be considered as paedomorphic rays nomic distinctions unless it is discovered in more gen (Carlquist, 2001a; fig. 6.2). Species with paedomorphic era and species that form well-supported systematic rays include Antigonon leptopus, Atraphaxis pungens, groupings within the family. Bilderdykia rnultiflora, Coccoloba cereifera, Dedeckera Eriogon urn appears to be a distinctive group on the eurekensis, Eriogonuni spp., Harfordia macroptera, basis of silica bodies, narrow multiseriate rays (nearly Muehlenbecki.a a.stonii. Polygonurn lapathifoliurn, all biseriate), lack of septa in fibres, and presence of Rurnex giganteus, and R. lunania. Because these have few cells (often only one) per strand in axial paren paedomorphic rays, they probably represent deriva chyma. There are, however, distinctive wood features tion from herbaceous or less woody ancestors, rather within Eriogonurn (pervasive parenchyma in F. than from clearly woody ancestors, according to con alatu and F. latifoliurn; raylessness in F. kennedyi; cepts of paedomorphosis in wood (Carlquist, 2001a). helical thickenings in vessels of F. giganteurn and The sole exception is Coccoloba cereifera, for which a FL heerrnannii and in vasicentric tracheids of twig from an herbarium specimen was used. Such a F. kennedyi). The sampling of woody species of En twig would be expected to have juvenile wood; in the ogonurn from western North America studied here other species listed above, juvenilism in rays is represent.s on’y a small portion of this group. Further extended for the life of the plant. Aside from the ray study of these would probably reveal many differences histology, the species in the above list do not suggest in wood, mostly related to habit and ecology. Axnaz true woodiness in aspect (e.g. Polygonurn, Rurncx) A ingly, this large group of distinctive species of En detailed molecular phylogeny of Polygonaceae is ogonuin were nearly all reduced to a single species needed to confirm this interpretation. As a whole, of the south-eastern U. S.. F. tornentosurn Mich., by Polygonaceae appear to be derived from woody ances Robert3’ & Vautier (1964). tors. Maekawa (1964) places the arborescent tribes Other distinctions in wood anatomy that may prove (subfamilies of other authors) Coccolobeae and to parallel generic taxonomic distinctions include Triplaridae at the base of his phylogenetic series for occurrence of successive cambia (Antigonon), vessel the family. This interpretation agrees with the data dimorphism (Bildendykia), Homogeneous Type II rays from rays. The phylogenetic arrangement of Dammer (Syrnrnenia), co-occurrence of silica bodies and calcium (1893) places Coccoloba and Triplaris (and allied gen oxalate crystals (Gyrnnopodiurn), and occurrence of era) near the end of his treatment, whereas the loca numerous calcium oxalate crystals within nonseptate tion of these woody genera by Roberty & Vautier fibres (Hanfordia). With these genera, as well as with (1964) is intermediate within the family. other groupings that seem at present to correlate with Dimorphism in vessel element diameter (and taxonomy, much more study is needed, because Polyg length: narrower vessel elements are appreciabi onaceae is a family with 49 genera and 1095 species longer) occurs in Antigonon and Bilderdykia. both of (Thorne, 2000). which are lianas. Antigonon is the only genus of Polyg More extensive systematic conclusions will be pos onaceae known to have successive cambia. Both of sible when the series of papers on Caryophyllales, these features are found in a much higher proportion which includes the present paper, is concluded. of lianas than in nonscandent woody dicotyledons (Carlquist, 1985.

HAmT Polygonaceae are relatively uniform with respect to ECOLOGY the F/V ratio (Table 1, column 17). One might have The arbitrary ratio termed Mesomorphy (Table 1, col expected great elongation of libriform fibres in trees umn 18) has proved useful when comparing families, such as Tniplanis. The significance of the F/V ratio genera, and species of dicotyledons (Carlquist & (which admittedly has a limited range) appears to rep Hoekman, 1985). For most dicotyledon families of resent, in a very general way, the degree of phyletic medium size, such as Pittosporaceae, the values range advancement (Carlquist, 1975). Imperforate tracheary range mostly between 50 and 150. The total range in elements are only a little longer than the vessel ele Pittosporaceae is 23—165 (Carlquist, 1981). In Polygo ments with which they are associated in dicotyledons naceae, the total range is from 0.49 to 34 173 (Table 1, widely regarded as primitive (Bailey & Tupper, 1918;’. column 18). In view of the mean Mesomorphy figures Ray cells are a very sensitive indication of habit and for Californian desert shrubs (20.9), riparian trees of ontogenetic and phyletic change in habit. There is (253) and woodland trees (1950). the range of values in an assumption (Kribs. 1935) that cells seen as square Polygonaceae is extreme. Ten of the 32 species studied in radial section are morphologically equivalent to here had values lower than the mean for southern Cal-

© 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 25—51 WOOD ANATOMY OF POLYGONACEAE 49 ifornian desert shrubs. the most xeric category in the on comparative grounds. Certainly some groups with southern Californian flora. Nine of the 32 had values vestured pits have succeeded well in xeric habitats higher than the means for southern Californian wood (Eucalyptus). Vestured pits may persist in some basi land shrubs, the most mesic category in the Califor cally xeric groups that have shifted into mesic ecolog nian flora. Thus, Polygonaceae show exceptional ical niches; presence of vestured pits is probably not a radiation into very wet as well as very dry areas as nonadaptive feature, although it may have originated well as many habitats in between, and to suit these in a limited number of phylads for genetic and mor habitats with the formulation of their wood. Plumbag phogenetic reasons. Experimental work on the fimc inaceae. sister family to Polygonaceae, has extremely tioning of vestured pits in comparison to that of xerornorphic wood. The average mesomorphy ratio fig nonvestured pits is very much needed. ure for Plumbaginaceae as a whole is 4.1, and the Another indication of the wide range of adaptation range is from 0.5 (Arnteria rnoritirna Li to 30 (Plum of Polygonaceae can be seen in the high proportion of bago capensis Thunb.) The lowest figure in Polygo species with growth rings. Only Synuneria and two naceae (0.49 in Antigonon leptopus) is not really species of Coccoloba are reported to lack any percep comparable to other values, since transverse section tible growth ring formation. The presence of vascular areas viewed for this analysis included conjunctive tis tracheids and extremely narrow vessels characterizes sue as well as secondary xylem; however, most species the latewood of many species (see Fig. 18, for with successive cambia do not. have markedly xero example). morphic wood (Carlquist, 1975). Although foliar characteristics in many dryland In dicotyledons that have fibre-tracheids or libri Polygonaceae are xeromorphic (drought-deciduous form fibres rather than tracheids sensu I. W. Bailey, leaves, linear leaves with inrolled margins, small leaf IAWA Committee oil Nomenclature (1964); Carlquist, area, thick cuticularization of leaf epidermis), wood is 2001a, and others), degree of vessel grouping corre obviously related to the adaptation of so many species lates with other xeromorphic wood features and to exceptionally dry areas. The occurrence in the same reflects the xeric nature of habitats (Carlquist, 1984). family of both highly xeromorphic and mesomorphic In Polygonaceae, this correlation is evident. The spe woods (Triplaris is typical of the latter) is perhaps cies with exceptionally large groupings of vessels unexpected because woody representatives of several either: (1) grow in notably dry habitats (Atraph axis other families of Caryophyllales favour drier habitats pungens, Dedeckcra eurekensis, Muehlenbeckia asto and have been unable to enter mesic habitats like flu): (2) are lianas, with attendant vessel dimorphism tropical rain forests: Caryophyllaceae (Carlquist, (Antigonon leptopus, Bilderdykia multiflora), or (3 are 1995) and Plumbaginaceae Cariquist & Boggs, 1996) ‘woody herbs’ in which stems flower as soil moisture are exemplary in this regard. Polygonaceae thus is a decreases markedly (Polygonunm). The low mean num family in which ecological shifts have been numerous ber of vessels per group for Coccoloba, Ruprechtia, and extreme, and wood has played a decisive role in Svrnrneria, and Triplaris correlates with the status of these shifts. these genera as elements of moist tropical forest (with freshwater readily available from a water table if not REFERENCES at the soil surface). The vessels per group figures for Eriogonum spp. may not seem very elevated, but they Bailey 1W. Tupper WW. 1918. Size variation in tracheary are certainly higher than those of the genera with ceHs. I. A comparison between the secondary xylems of vas more mesomorphic woods. In Eriogonuni and Calli cular cryptogamns, gymnosp€rrns, and angiosperms. Proceed gonuin, the mean number of vessels per group and (rigs of theArnericanAcadem-v of Arts and Sciences 54: 149— vessel density may not be spectacularly large (com 204. pare to Cassiope with about 2000 vessels mm2: Behuke 11-D, Mabry TJ. 1994. Caryophylloles. Evolution Wallace, 1986), but there are large latewood vessel and systematics. Berlin: Springer Verlag. Cariquist S. 1975. Ecological groupings, where resistance to embolism through nar strategies of xylem evolution. Berkeley: University of California Press. row conduit diameter (Hargrave et al., 1994) is most Carlquist S. 1981. Wood anatomy of Pittosporaceae. important. Thus, both large vessel groups and very Allertonia 7: 355—391. narrow vessels occur conjunctively in latewood and Carlquist S. 1982. The use of ethyleae diamine in softening probably serve to maintain water columns to foliage hard plant structures for paraffin sectioning. Stain Technol during dr seasons. ogy 57: 311—317. The presence of vestured pits, probably very com Cariquist S. 1984. Vessel grouping in dicotyledon woods: mon in Polygonaceae, might be another feature that significance and relationship to imperforate tracheary ele aids survival under conditions of low moisture avail ments. Aiiso 19: 505—525. ability. If one looks at the systematic distribution Carlquist S. 1985. Observations on functional wood histology (Jansen et al., 1998), there is no clear interpretation of vines and lianas: vessel dimorphism, tracheids, vasiceatric

tracheids. narrow vessels, and parenchrma. Aliso 11: 139— Horak XE. 19811,. The three-dimensional structure of 157. vascular tissues in Stegnosperrna (Phytolaccaceae). Botani Cariquist S. 1995. Wood anatomy of Caryophyllaceae: ecolog cal Gazette 142: 545—549. ical, habital. systematic, and phylogenetic implications. IAWA Committee on Nomenclature. 1964. Multilingual Aliso 14: 1—17. glossary of terms used in wood anatomy. Winterthur: Carlquist S. 1999a. Wood aad stern anatomy of Strgnospermo Konkordia. (Caryophylla]es); phylogenetic re]ationships; nature of lat IAWA Committee. 1989. List of microscopic features for hard eral meristems and successive camhial activity. IAWA wood identification. JAWA Bulletin, New Series 2: 99—145. Journal 20: 149—163. Jansen 5, Smets E, Baas P. 1998. Vestures in woody plants: Cariquist S. 1999b. Wood anatomy, stem anatomy, and cam a review. IAWA Journal 19: 347—382. bial activity of Barbeuia (Caryophyllales). JAWA Journal 20: Kribs DA. 1935. Salient lines of specialization in the wood 431—440. rays of dicotyledons. Botanical Gazette 96: 547—557. Cariquist S. 1999c. Wood, stem, and root anatomy of Basel Kucera 1.5, Meylan BA, Butterfield BG. 1977. Vestured lacene with relation to habit, systematics, and cambial vari simple perforation plates. IAWA Bulletin, N. S. 1: 3—6. ants. Flora 194: 1—12. Maekawa F. 1964. On the phlogeny in the Polygonaceae. Cariquist S. 2000. Wood and stern anatomy of phytolaccoid Japanese Journal of Botany 39: 366—370. and rivinoid Phytolaccaceae (Caryophyllalesi. Aliso 19: 13— Manhart Sit, Rettig Jil. 1994. Gene sequence data. In: 29. Behnke H-D, Mabry TH, ads. Carvophyllales. Evolution and Carlquist S. 2001a. Comparative wood anatomy, 2nd Ed. systematic’s. Berlin: Springer Verlag. 235—246. Berlin: Springer Verlag. Metcalfe CR, Chalk 1.. 1950. Anatomy of the divotyledons. Cariquist S. 2001b. 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Berlin: Springer Verlag. 279—301. 6: 319—347. Solereder H. 1908. Systematic anatomy of the dicotyledons Cronquist A, Thorne RE. 1994. Noinenclatural and taxo (translated by LA Boodle, FE Fritsch). Oxford: Clarendon nomic history. In: Behnke HD, Mabry T’J, eds. Car-yophyl Press. tales, Evolution and systematics. Berlin: Springer Verlag, 5— Soltis DE, Soltis PS, Chase MW, Mort ME, Albach DC, 25. Zanis M, Savolainen V, Hahn WH, Hoot SB, Pay MF, Dammer U. 1893, Polygonaceae. In: Engler A, Prantl K, eds. Axtell M, Swensen SM, Prince LM, Kress WJ, Nixon Die Naturlichen Pfianzenfa,nilien III (la). Leipzig: Verlag KC, Farris JS. 2000. Angiosperm phylogeny inferred from Engelmann, 1—36. 1SS rDNA, rbcL, and atpB sequences. Botanical Journal of Downie SR, Katz-Downie DS, Cho IC-S. 1997. Relationships the Linneon Society 133: 38 1—461. in the Caryophyllales as suggested by phylogenetic analyses Thorne RE. 2000. The classification and geography of the of partial chloroplast DNA 0RG2280 homolog sequences. flowering plants: dicotyledons of the class Angiospermae American Journal of Botany 84: 253—273. (subclasses Magnoliidae, Ranunculidae, Caryophyflidae, Downie SR. Palmer lED. 1994. Phylogenetic relationships Dilleniidae, Rasidae. Asteridae, and Lamiidae. Botanical using restriction site variation of the chloroplast DNA Review 66: 441—647. inverted repeat. In: Behnke H-B, Mabry TH, eds. Canophvl Wallace GD. 1986. Wood anatomy of Cassiope cEricaceae). tales. Evolution and aystematics. Berlin: Springer Verlag, Atiso 11: 393-415. 225—233. Williams SE, Albert VA, Chase MW. 1994. Relationships of Eichler AW. 1876. Syllabus der Vorlesungen uber Phaneroga Droseraceae: a cladistic analysis of rbcL sequence and mor menkunde. Kid: Schwer’sche Buchhandlung. phological data. American Journal of Botany 81: 1027—1037. Gregory M. 1994. Bibliography of systematic wood anatomy of dicotyledons. IAWA Journal, Supplement 1: 1—265. APPENDIX Hargrave KR, KoIb ICJ, Ewers FW. 1994. Conduit diameter and drought-induced embolism in Salvia mellifera Greene. SPECIMENS STUDIED New Phytologist 126: 695—705. Antigonon leptopus Hook. & Aim, cult. National Tropi Horak XE. 1981a. Anomalous secondary thickening in Step cal Botanical Gardens, Kauai, Hawaii, Cariquist, s. n. oosperma (Phytolaccaceae). Bulletin of the Torrey Botanical Atraphoxis pungens Jaub. & Spach, Turkmenistan, Club 108: 189—197. Elias 7571 IRSA).

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Bilderdykia multiflora Robertv & Vautier, SFCw B. kennedyi Porter cx XVats., Mt. San Antonio, Califor R1213-40 nia, Carlquist, s. n. Calligonuin arborescens Litv.. Arabia, Aw-22928. Gvmnopodium antigonoides S. F. Blake, Belize, USw C. comosum L’Her., Turkestan, Podgorski 801 tRSA) 13555. Coccoloba cereifera Schwant., Brazil, Eiten 6786 (RSA). Harfordia macroptera (Benth.) Greene & Parry, N. Baja C. laurifolia Jacq., Florida, USw-3544 (in RSAw). California, Mexico, Davidson 5487 (RSAw). C. longifolia Fisch., Jamaica, USw-5918 (in RSAw). Muehlenbeckia ostonii Petrie, cult. University of Auck C. polvstachya Wedd., Brazil, Krukoff 6114. USw (in land, Carlquist 8092 (RSAw). RSAw). Neornillspaughia ernarginata (Donn.-Sm.) S. F. Blake, C. rotundifolia Meissn in DC., Haiti, USW-4334 (in Mexico. USw-13569 (in RSAw). RSAw). Polvgonurn lapathifoliurn Aiton, Peru. Carlquist 7161 C. rugosa Desf., Jamaica, USw-5943 (in RSAw). (RSAw). C. uvifera Jacq.. Florida. USw-20667 (in RSAwJ. Humeri giganteus Aiton. Maui, Hawaii, Carlquist 2060 Dedeckera curehensis Reveal & 3. 1 Howell, Eureka (RSAw) Dunes, California, D. Wiens. s. n. R. lunaria L., Tenerife, Canary Islands, Carlquist 2429 Eriogonum arborescens Greene, Santa Cruz 1.. Califor (RSAw). nia, Raven 15832 (RSAw). Ruprechtia sp., Misiones, Argentina, BAw-52595. B. deserticola S. Wats., Imperial Co, California & Wolf Symmeria paniculata Benth., Brazil, Krukoff 6749 1868 (RSAw). (RSAw). B. fasciculata Benth., Claremont, California, Carlquist, Triplaris americana L., Venezuela, ZTw, s. n. (in RSAw). 5. IL T melanodendron Standl. & Steyerm., Panama, lJSw E. giganteum S. Wats., Santa Catalina I. & Carlquist 103 (in RSAw. 1820 (RSAw). T pavonii Meisn., Brazil, Krukoff 6249 (USw in RSAw). E. heermanii Dur. & Hilg., southern California, David T surinamensis Cham.. Surinam, Stahel 50 (RSAw. son 4258 (RSAw).