Systematics of Croizatia (Euphorbiaceae)herbarium.ucdavis.edu/publications/webster/75.Systematic...Systematics of Croizatia (Euphorbiaceae) GRADY L. WEBSTER and LYNN GILLESPIE Botany

Systematic Botany (1987), 12(1): pp. 1-8 C Copyright 1987 by the American Society of Plant Taxonomists

Systematics of Croizatia (Euphorbiaceae)

GRADY L. WEBSTER and LYNN GILLESPIE

Botany Department, University of California, Davis, California 95616

JULIAN STEYERMARK

Missouri Botanical Garden, St. Louis, Missouri 63166

ABSTRACT. Croizatia, a genus known from Panama and Venezuela (Euphorbiaceae, Phyllanthoi- deae), has been considered closely related to the Old World genus Actephila. However, the spinose pollen of Croizatia is very different from the semitectate pollen of Actephila, and the two genera appear clearly distinct. The pollen morphology of Croizatia suggests a possible relationship with the Oldfieldioideae, and it may be the closest extant taxon to a connecting link between the subfamilies. Three species of Croizatia are tentatively recognized, including a new species, Croizatia panamensis; but species delimitations must be regarded as provisional.

The Euphorbiaceous genus Croizatia (Steyer- mark 1952), named for the eminent student of the systematics of the Euphorbiaceae, Leon Croizat-Chaly (Steyermark 1983), has long been regarded as of uncertain affinity. The first species published, C. neotropica (Steyermark 1952), was described from a fruiting specimen collected in the state of Anzoategui, Venezuela. Later, Steyermark (1978) added a second species, C. naiguatensis, from another fruiting specimen found on the Cerro Naiguata, Distrito Federal, Venezuela.

Croizat (in Steyermark 1952) stated that the affinities of Croizatia were close to the Old World genus Actephila. In 1978, when C. naiguatensis was described, the flowers of both species were still unknown, and the affinities of the genus therefore remained problematical. In the most recent enumeration of Euphorbiaceous genera (Webster 1975), Croizata was omitted because of its dubious status; but in the synoptic arrange- ment of tribes of Phyllanthoideae (Webster ined.) its placement appeared to be with either the Wielandieae or Amanoeae. Levin (1984), in a survey of leaf characters in the Phyllanthoi- deae, reports a greater similarity of Croizatia to Savia and Blotia than to Actephila.

Recently in June 1983, our knowledge of the reproductive morphology of Croizatia im- proved dramatically due to the collection of flowering specimens of C. naiguatensis. The petaliferous flowers (fig. 1) resemble those of Ac- tephila, as Croizat had predicted; there is an es- pecial similarity to the flowers of the widespread paleotropical species Actephila excelsa (Dalz.) Muell. Arg. The major floral dif-

ferences observed are the much more reduced petals of staminate flowers and the twice bifid style tips of Croizatia. Although there are other diagnostic characters pointed out by Steyer- mark (1952), such as the enlarged columella of Croizatia, the overall gross resemblance to Ac- tephila is striking. Indeed, Gentry (1982) has at- tributed to Rodriguez an unpublished combi- nation under Actephila for C. neotropica and quotes Rodriguez as stating that Croizatia is in- distinguishable from Actephila.

Despite the uncertainty regarding the gener- ic status of Croizatia, the floral, fruit, and leaf characters appear to provide sufficient distinc- tions to maintain it as separate from Actephila. Furthermore, examination of the pollen grains with scanning electron microscopy shows that the pollen of Croizatia (figs. 2, 3) is very different from that of Actephila collinsae Hunter (fig. 4). The pollen grains of A. collinsae are 40-49 (x = 46) Am in diameter, subprolate, and tricolporate with large, well-defined colpi; the exine is rather finely semitectate-reticulate. These characters agree rather well with the light mi- croscopic observations on other species of Ac- tephila: A. excelsa (Punt 1962), A. nitidula Gag- nep., and A. ovalis Gagnep. (Kohler 1965). Both Punt and Kohler have noted the resemblance of the pollen grains of Actephila to those of An- drachne (s.l.). In contrast, the pollen grains of Croizatia naiguatensis are spherical, 46-56 (x = 51) Am in diameter, with the colpi greatly shortened (ca. 10 ,um long), the lalongate germ pore well developed (ca. 10 Am broad); the exine is tectate-perforate and ornamented with conical, sharply-pointed spines ca. 3-4 Am high.

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FIG. 1. Habit and flowers of Croizatia naiguatensis. A. Pistillate branch with fruits and flowers. B. Part of staminate branch with flowers. C. Staminate flower with one petal enlarged. D. Pistillode. E. Sta- men. F. Pistillate flower with one petal enlarged. G. Gynoecium with disk, petals, and staminode. H. Cross-section of ovary. I. Columella and persistent calyx on fruiting pedicel.



1987] WEBSTER ET AL.: CROIZATIA 3

7 v,

FIGS. 2-7. Pollen grains of Euphorbiaceae; scales = 10 ,um. 2, 3. Croizatia naiguatensis (Berry et al. 4124, DAV). 4. Actephila collinsae (Larsen 33631, MO). 5. Tetracoccus dioicus (Carlquist s.n., cult. Rancho Santa Ana Botanic Garden). 6. Podocalyx loranthoides (Williams et al. 18249, DAV). 7. Amanoa guyanensis (Tillett & Tillett 45256, DAV).




TABLE 1. Comparison of morphological characters of Croizatia with those of Phyllanthoideae and Oldfield- ioideae.

Phyllanthoideae Croizatia Oldfieldioideae

Phyllatoxy alternate alternate alternate, opposite, or whorled Stipules usually + + +, reduced, or 0 Petals + or 0 + 0 Staminate mostly extrastaminal extrastaminal mostly intrastaminal or 0

disk Pollen mostly 3-4-colporate, brevicolpor- brevicolporate or pororate,

not echinate ate, echinate echinate Ovules anatropous/hemitropous hemitropous anatropous Styles mostly bifid twice bifid mostly simple Seeds ecarunculate ecarunculate carunculate or ecarunculate Endosperm +/0 0 +

This striking difference between the pollen grains of Croizatia and those of Actephila rein- forces the impression, based on gross morphological characters, that the two genera are quite distinct.

On the other hand, the echinate, tribrevicol- porate pollen found in Croizatia is clearly sim- ilar to pollen of Oldfieldioideae as that group was palynologically defined by Kohler (1965) and taxonomically delimited by Webster (1967). There is a close resemblance between the pollen of C. naiguatensis and that of Tetracoccus dioicus Parry (fig. 5) and Podocalyx loranthoides Klotzsch (fig. 6), which are considered to be two of the more primitive members of the Old- fieldioideae on the basis of floral and vegeta- tive characters (Webster ined.). Podocalyx differs from Croizatia in having tetraporate pollen with a tectate-imperforate exine and in its dis- tinctly smaller diameter (ca. 30 A,m), while Tet- racoccus differs in having 4- to 6-colpoidorate pollen and a tectate-regulate exine with gem- mae on the ridges.

Within the Phyllanthoideae, true spines of the "Oldfieldioid" type have heretofore been unrecorded. The pollen grains of some species of Amanoa are irregularly baculate; the sculptural elements are rod-like with the apex some- times expanded or tapered (fig. 7). The different structure of the "spines" in both Croizatia and Amanoa suggests that the resemblance may be due to convergence and, therefore, not in- dicative of a close phylogenetic relationship. Another taxon within the Phyllanthoideae which has pollen that bears some resemblance to pollen of the Oldfieldioideae is Securinega durissimna J. F. Gmel., illustrated by Webster

(1984b); the pollen is oblate, tricolporate with colpi short but not greatly reduced and with a tectate-regulate exine with supratectal spinu- lose sculptural elements. Although Securinega has been traditionally placed in the Phyllan- theae, this appears to have been due to the er- roneous inclusion of species properly referable to Flueggea (Webster 1984a). The pollen of the type species S. durissima is quite anomalous within the tribe and resembles to a much greater extent pollen of members of the Wielandieae, such as Discocarpus. The "S. durissima" pollen type might conceivably bear an ancestral relationship to typical "Oldfieldioid" pollen; however, much further study is needed concerning the taxonomic position of S. durissima and other Wielandieae before possible links to the Oldfieldioideae can be substantiated.

When the characters of Croizatia are tabulated in comparison with the Phyllanthoideae and Oldfieldioideae (table 1), it clearly agrees better with the Phyllanthoideae in five characters (petals, staminate disk, ovules, styles, and de- velopment of endosperm) and with the Old- fieldioideae in only one (pollen). However, most of the resemblance to the Phyllanthoi- deae involves the common possession of primitive (plesiomorphic) characters. When only derived (apomorphic) characters are considered, Croizatia has two in common with Phyl- lanthoideae (hemitropous ovules, exalbuminous seeds) and one with Oldfieldioideae (echinate pollen).

In table 2, the characters of Croizatia are con- trasted with two putatively primitive genera, Wielandia and Podocalyx, in the subfamilies Phyllanthoideae and Oldfieldioideae. Here the




TABLE 2. Comparison of morphological characters of Croizatia with a primitive genus of Phyllanthoideae (Wielandia) and a primitive genus of Oldfieldioideae (Podocalyx).

Wielandia Croizatia Podocalyx

Petals + + 0 Staminate extrastaminal, annular extrastaminal, annular 0

disk Anthers introrse introrse extrorse Pollen 3-4-colporate, not echinate 3-brevicolporate, echin- 4-pororate, echinate

ate Ovary glabrous glabrous pubescent Ovules anatropous hemitropous anatropous Styles bifid twice bifid stigmatiform Seeds not black and shiny not black and shiny black and shiny Endosperm 0 0 +

resemblance with Wielandia is especially striking, since there are six characters in common that are not shared with Podocalyx. Actephila, the genus resembling Croizatia in aspect, shares these same characters. In contrast, Podocalyx shares only a single character (pollen exine or- namentation) not possessed by Wielandia and Actephila. However, Croizatia has only one derived character in common with Wielandia (lack of endosperm) and one with Podocalyx (echinate pollen).

The available morphological data on the Phyllanthoideae are still so incomplete that at present it would be premature to attempt a de- tailed cladistic or phenetic analysis. For the present, we are dependent on the character contrasts presented in tables 1 and 2, and unfortunately they tell discordant stories. Croiza- tia shares two derived characters (hemitropous ovules and exalbuminous seeds) with the Phyl- lanthoideae (although only one with any single genus), while it shares only the echinate pollen character with the Oldfieldioideae. One could argue that on cladistic, as well as phenetic, grounds placement of Croizatia in the Phyllanthoideae is indicated. On the other hand, the single pollen character shared with Oldfieldioideae involves a complex of features (spine morphology, shortening of colpus, germ pore configuration), and it seems rather less likely to have evolved independently in different lineages. We thus end on the horns of a dilemma of "quantity" versus "quality" in evaluation of derived characters.

These problems in determining the phylogenetic position of Croizatia also raise difficul- ties in demarcating the boundary between the

subfamilies Phyllanthoideae and Oldfieldioi- deae. If Croizatia indeed represents an ancestral link to the Oldfieldioideae, its inclusion on cladistic grounds would result in the introduction of several discordant characters (petaliferous flowers, extrastaminal disk, hemitropous ovules, bifid styles, and exalbuminous seeds) into the subfamilial diagnosis of the Oldfieldioideae. However, its placement in the Phyllanthoideae would not change the status of the Phyllan- thoideae as a paraphyletic group, since that subfamily would be paraphyletic in any cir- cumscription (due to its having given rise to the subfamily Acalyphoideae as well) that has been proposed up until now. In the face of in- adequate data and the problems of analysis dis- cussed above, it seems expedient to assign Croi- zatia provisionally to the Phyllanthoideae, where it can be placed between Blotia and Ac- tephila.

Although these problems of classification are challenging and interesting, study of the morphology of Croizatia is most significant in elu- cidating phylogenetic and biogeographic relationships. The link between Croizatia and Podocalyx clearly suggests that the Oldfieldioi- deae is of South American origin, even though the living taxa now occur widely in other parts of the southern hemisphere (Africa, Madagas- car, Ceylon, Indonesia, and Australasia). Croiza- tia and Actephila are vicariants of West Gon- dwanaland and East Gondwanaland, respectively (sensu Raven and Axelrod 1974). The progenitor of Croizatia presumably migrat- ed from Africa/Madagascar, where the primitive Phyllanthoideae are concentrated, across a narrower Atlantic; but since Actephila is known




only from India to Austalasia, other now-ex- tinct taxa may have been involved. Martin (1974, 1982) indicates that relatively advanced Oldfieldioideae of the Austrobuxus alliance were present in Australasia in the Paleocene, so that the initial differentiation of Croizatia would appear to have been in the late Cretaceous.

SYSTEMATIC TREATMENT

CROIZATIA Steyermark, Fieldiana 28:308, fig. 57. 1952.-TYPE: Croizatia neotropica Steyerm.

Dioecious trees or shrubs; indumentum simple. Leaves alternate, entire, pinnately veined, without embedded glands, petiolate; stipules deciduous or persistent. Flowers in axillary clusters; bracts inconspicuous. Staminate flowers pedicellate; sepals 5, imbricate, entire; petals 5, much shorter than sepals, pubescent, entire; disk annular, glabrous; stamens 5, free, anthers introrse; pollen grains globose, exine with conical spines; pistillode trifid. Pistillate flowers pedicellate; sepals 5, imbricate, entire, persistent in fruit; petals 5, much shorter than sepals, pubescent, entire; disk annular, glabrous; ovary pubescent, 3-locular; styles free, slender, twice bifid; ovules paired in each locule, hemitropous. Fruit a capsule; columella distally expanded into 3 broad papery wings; seeds paired or solitary in each locule, smooth, not fleshy, ecarunculate; endosperm absent; cotyledons greenish, contortuplicate, much broader than and about as long as the radicle.

KEY TO THE SPECIES

Fruiting pedicels not over 2 cm long; lateral nerves of leaf blades 7-10 . 2. C. naiguatensis

Fruiting pedicels over 2 cm long; lateral nerves of leaf blades 12-15 on each side.

Fruiting pedicels glabrous, 3.5-4.5 cm long; seeds 10.5-12 mm long .... 1. C. neotropica

Fruiting pedicels pubescent, 2.5-3.5 cm long; seeds 7.2-10 mm long .... 3. C. panamensis

1. CROIZATIA NEOTROPICA Steyermark, Field- iana 28:309, fig. 57. 1952.-TYPE: Venezue- la, Anzo'ategui, Quebrada Seca, E of Ber- gantin, 18 Mar 1945, Steyermark 61523 (holotype: VEN!).

Additional collection. VENEZUELA. Anzoategui: Distrito Bolivar, Fila El Guacharo, Serrania de Turi- miquire, 1200-1350 m, 25 Nov 1981, Davidse & Gon- zalez 19452 (F, MO).

Unfortunately, the newer collection bears only fruits, and the flowers of Croizatia neotropica are still unknown. A collection with pistillate flowers from Peru (Amazonas, Serrania de Bagua, Gentry et al. 22989, F, MO) resembles Croizatia neotropica in some respects, but its as- signment must be regarded as uncertain.

2. CROIZATIA NAIGUATENSIS Steyermark, Brit- tonia 30:40, fig. 1. 1978.-TYPE: Venezuela, Distrito Federal, Cerro Naiguatia, upper reaches of Quebrada del Mata de Platano, 2000 m, 7 Dec 1973, S. Tillett, G. & B. Morillo & B. Manara 82 (holotype: VEN!; isotype: DAV!).

Tree 5-7 m high; leaf blades elliptic to obovate, acute or obtuse (less often rounded) at tip, long-attenuate at base, 9-21 cm long, 4-9 cm broad, glabrous or inconspicuously strigose beneath, lateral nerves 7-10 on each side, somewhat prominulous with the more delicate tertiary veinlet network; petioles 4-9 mm long, stout, glabrous or strigose; stipules scarious, striate, brownish, 7 mm long, deciduous. Sta- minate flowers in dense axillary clusters; pedicel 3-4 mm long, hirtellous; sepals 5, elliptic, entire, 4-4.5 mm long, 2.5-3 mm broad; petals 5, obovate, subentire, densely long-ciliate, 1- 1.3 mm long, and broad; disk massive, smooth and glabrous, 2.5-3 mm across; stamens 5, fil- aments 2.2-2.5 mm long, hirsutulous below; anthers elliptic, 1.2-1.4 mm long; pistillode 3-lobed, hirsutulous, 1.8-2.2 mm high. Pistil- late flowers solitary; pedicel strigillose, becoming 8-12 mm long in fruit; sepals 4 or 5, lanceolate, obtuse or acute to rounded, strigillose, becoming reflexed and persistent in fruit, 8-10 mm long, 2-3 mm broad; petals (4)5, broadly obovate or suborbicular, ca. 1 mm long and broad, densely ciliate; disk cupuliform, glabrous, entire, ca. 0.4 mm high and 3.5 mm broad; ovary sericeous; styles spreading, 2.8-3 mm long, twice bifid, the unbranched portion 1.5-2 mm long, the primary branches 1.2-1.5 mm long, ultimate tips 0.3-0.5 mm long. Cap- sule oblate, 3-lobed, 1.3-1.4 cm high, 1.7-2 cm broad, strigillose, reticulate; columella 7-8 mm long, dilated at apex into 3 obovate-oblong wings rounded at apex, 7 mm long, 5 mm broad. Seeds unknown.

Additional collection. VENEZUELA. Vargas: trail from Pico de Naiguata to town of Naiguata, Fila del




4cm ^

1 cm

FIG. 8. Croizatia panamensis. a. Habit. b. Fruiting calyces (Garcia-Barriga 11175, COL).

Corozo, 24 June 1983, P. Berry et al. 4121, 4124 (DAV, VEN).

Although the recent collection of flowering material of Croizatia naiguatensis provides for the first time an understanding of the floral morphology of the genus, it is difficult to compare it with the other two species because of the incompleteness of the collections. It differs from both C. neotropica and C. panamensis in its smaller leaves with fewer lateral veins and shorter fruiting pedicels; it agrees with C. neotropica in its deciduous stipules but differs in its pubescent pedicels.

3. Croizatia panamensis Webster, sp. nov. (fig. 8).-TYPE: Panama, Panama, primary forest along road from El Llano to Carti-Tupile, 300-500 m, 30 Mar 1973, L. L. Liesner 1279 (holotype: MO!; isotype: DAV!).

Ab C. neotropica differt pedicellis brevioribus seminibus parvioribus, ab C. naiguatense differt foliis majoribus stipulis persistentibus, pedicil- lis longioribus.

Shrub or small tree 1-6 m high, usually with a single main stem; leaf blades chartaceous, glabrous or sparsely strigose-hispidulous beneath, obovate, abruptly short-acuminate, basally attenuate, 22-45 cm long, 5-12 cm broad, with ca. 15 arcuate-ascending lateral nerves con- nected by intramarginal loops, veins (and to a lesser extent) veinlets prominulous beneath; petioles 0.5-1 cm long and 3-4 mm thick; stipules more or less persistent, oblong-lanceolate, acuminate, ribbed sericeous, 10-20 mm long, 6-7 mm broad. Flowers not observed. Fruiting pedicels hirtellous, 2.5-3.5 mm long, 1.2-2 mm thick; sepals more or less persistent in fruit, reflexed, elliptic-lanceolate, acute or subacute, 8-9 mm long, 3-3.2 mm broad, exter- nally hispidulous; columella ca. 8-9 mm high, 10-11 mm broad; seeds trigonous, smooth, brownish, 7.2-10 mm long, 5.3-6.5 mm broad, hilum medial, ca. 2 mm broad; cotyledons ca. 10 mm long, radicle ca. 5 mm long.

Additional collections. COLOMBIA. Choc6: Villa- conto, cerca de los rios Quito y Palmado, 120 m, 1




Aug 1944, Garcia-Barriga 11161 (US), Garcia-Barriga 11175 (COL).

This species is proposed with some hesita- tion because of the lack of flowering material. However, it appears to differ from Croizatia neotropica and C. naiguatensis in habit (the scarcely branched stems contrasting with both other species) and in the more-or-less persistent stipules. It diverges from C. neotropica in its shorter strigillose fruiting pedicels and smaller seeds, and from C. naiguatensis in its larger leaves and longer fruiting pedicels. Until flowering material of both C. panamensis and C. neotropica is collected, further comparisons would be premature.

A very distinctive collection from Napo Province, Ecuador, 1llgaard et al. 38956 (AAU), resembles Croizatia panamensis, as pointed out by Dr. Michael Huft (pers. comm.). However, although it has the elongated persistent stipules and oblanceolate leaves of the Panama species, the Ecuadorian plant has much longer fruiting pedicels and more acuminate sepals. It may well prove to be a different species, but it does not seem advisable to describe it as new on the basis of the single collection.

ACKNOWLEDGMENTS. This study was supported in part by NSF grants and in part by grants from the Graduate Division and Botany Department, Univer- sity of California, Davis. Scanning electron micro- graphs were taken by Ms. Lynn Gillespie and Dr. Steven P. Lynch. Drawings of flowers were provided by Sr. Bruno Manara. We are indebted to Dr. Michael Huft of the Missouri Botanical Garden for making available some critical specimens.

LITERATURE CITED

GENTRY, A. H. 1982. Phytogeographic patterns as evidence for a Choc6 refuge. Pp. 112-136 in Biological diversification in the tropics, ed. G. T. Prance. New York: Columbia Univ. Press.

KbHLER, E. 1965. Die Pollenmorphologie der biov- ulaten Euphorbiaceae und ihre Bedeutung fur die Taxonomie. Grana Palynol. 6:26-120.

LEVIN, G. 1984. Systematic foliar morphology of Phyllanthoideae (Euphorbiaceae). Ph.D. disser- tation, Univ. California, Davis.

MARTIN, H. A. 1974. The identification of some Ter- tiary pollen belonging to the family Euphorbi- aceae. Austral. J. Bot. 22:271-291.

. 1982. Changing Cenozoic barriers and the Australian paleobotanical record. Ann. Missouri Bot. Gard. 69:625-667.

PUNT, W. 1962. Pollen morphology of the Euphor- biaceae with special reference to taxonomy. Wentia 7:1-116.

RAVEN, P. and D. AXELROD. 1974. Angiosperm bio- geography and past continental movements. Ann. Missouri Bot. Gard. 61:539-673.

STEYERMARK, J. 1952. Euphorbiaceae, in Botanical exploration in Venezuela-II. Fieldiana Bot. 28: 304-322.

. 1978. New taxa from the Avila and Nai- guata mountains, Venezuela. Brittonia 30:39-49.

. 1983. [Biographical note on] Leon Croizat- Chaly. Taxon 32:530-531.

WEBSTER, G. L. 1967. The genera of Euphorbiaceae in the southeastern United States. J. Arnold Arb. 48:303-430.

. 1975. Conspectus of a new classification of the Euphorbiaceae. Taxon 24:593-601.

. 1984a. A revision of Flueggea (Euphorbi- aceae). Allertonia 3:259-312.

. 1984b. Jablonskia, a new genus of Euphor- biaceae from South America. Syst. Bot. 9:229-235.



Article Contentsp. 1p. 2p. 3p. 4p. 5p. 6p. 7p. 8

Issue Table of ContentsSystematic Botany, Vol. 12, No. 1 (Jan. - Mar., 1987), pp. 1-186Front Matter [pp. ]Systematics of Croizatia (Euphorbiaceae) [pp. 1-8]Primula anvilensis (Primulaceae): A New Species from Northwestern Alaska [pp. 9-13]Karyotypes and Relationships among Bolandra, Boykinia, Peltoboykinia, and Suksdorfia (Saxifragaceae: Saxifrageae) [pp. 14-20]The Carpinus caroliniana Complex in North America. I. A Multivariate Analysis of Geographical Variation [pp. 21-40]Damnxanthodium (Compositae: Heliantheae), a New Genus from Mexico [pp. 41-43]Identity of Lantana depressa and L. ovatifolia (Verbenaceae) of Florida and the Bahamas [pp. 44-60]Field and Garden Studies of Arctostaphylos uva-ursi (Ericaceae) in North America [pp. 61-77]The Necessity of Convex Groups in Biological Classification [pp. 78-90]Relationships Among the Genera of Pinaceae: An Immunological Comparison [pp. 91-97]Implications of Pollen/Ovule Ratios and Pollen Size for the Reproductive Biology of Potamogeton and Autogamy in Aquatic Angiosperms [pp. 98-105]ReviewReview: untitled [pp. 105]

The Madrensis Group of Coursetia (Leguminosae: Robinieae) [pp. 106-115]Evidence for the Origin of the Hybrid Cliff Fern, Woodsia x Abbeae (Aspleniaceae: Athyrioideae) [pp. 116-124]Patterns of Isoenzyme Variation in Plectritis (Valerianaceae) [pp. 125-132]Boltonia apalachicolensis (Asteraceae): A New Species from Florida [pp. 133-138]Revision of the Lathyrus vestitus-laetiflorus Complex (Fabaceae) [pp. 139-153]Allozymic Differentiation Between Tolmiea menziesii and Tellima grandiflora (Saxifragaceae) [pp. 154-161]Two New Species of Elleanthus (Orchidaceae) from Ecuador and Peru [pp. 162-166]ReviewReview: untitled [pp. 166]

Flavonoid Chemistry of Polygonum Sect. Echinocaulon: A Systematic Survey [pp. 167-179]ReviewsReview: untitled [pp. 180-181]Review: untitled [pp. 181-182]Review: untitled [pp. 182-183]Review: untitled [pp. 183-184]

Back Matter [pp. ]

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Systematics of Croizatia (Euphorbiaceae)herbarium.ucdavis.edu/publications/webster/75.Systematic...Systematics of Croizatia (Euphorbiaceae) GRADY L. WEBSTER and LYNN GILLESPIE Botany