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Pollen grains of 23 species distributed in 15 genera and represented by 64 specimens were analysed using light and scanning electron microscopy to characterise the neotropical genera of Hippomaneae...

Stillingia aquatica, a wetland shrub in the Southeastern U.S., was profiled in Southeast Florida from a natural history standpoint. The stem has exceptionally lightweight wood in common with other periodically root-inundated woody plants. Pseudowhorled tufts of conspicuous yellow leaves subtend the similarly colored spikelike thyrsoid inflorescences. The plants are monoecious, self-compatible, protogynous with respect to inflorescences, and with a mixed mating system. After a pistillate-only phase, pistillate and staminate phases overlap in time, and are positioned in close physical proximity within inflorescences. Then follows a prolonged phase of only staminate flowers plus maturing fruits. The inflorescences attract ants, bees, and especially abundant wasps, switching from mixed bees and wasps in the dry season to essentially just wasps in the wet season. Wind-pollination is minimal to none. Ants are often abundant in the inflorescences and believed to contribute to geitonogamy but are not necessary for fruitset. Agamospermy is none to negligible. The seeds often fail, with the failure rates varying between populations and between individual plants.

In Euphorbiaceae tribe Hippomaneae is the pantropical genus Microstachys, comprised by 24 species, mostly from Brazil. Palynological studies with several representatives of the genus are sc...

Gradyana franciscana, a new genus and species of Euphorbiaceae found in the Sao Francisco river valley, in the semiarid region of northeastern Brazil, is herein described and illustrated. Gradyana is morphologically close to Stillingia due to the presence of carpidiophore and foliar glands, but differs in possessing strictly axillary sinuous thyrsoid staminate inflorescences, solitary pistillate flowers, apical glands in the bracts, long-stipitate glands between pistillate sepals, and staminate flowers with three stamens and three sepals. A key to differentiate Gradyana from other genera of the tribe Hippomaneae occurring in South America is presented. Comments about its geographic distribution, habitat, and conservation status are also provided.

— A new species of Actinostemon is described and illustrated. Actinostemon roselii is mentioned only for the states of Parana and Santa Catarina (Brazil), where it grows in riparian tropical rainforests. This species can be recognized by its conspicuous and depressed ovate bracts of the staminate cymule, foliar buds globoid, staminate cymule with three or four flowers, and staminate and pistillate flowers monochlamydeous. Comments about its distribution and ecology are provided, as well as a key to identify the Brazilian species of Actinostemon. Based on IUCN criteria, A. roselii can be considered a data deficient (DD) species.

The nomenclature of Dendrocousinsia (Hippomaneae, Euphorbiaceae) is revised and we present four new taxonomic combinations within the genus. It comprises six species and one variety. Extensive field surveys were conducted and conservation assessments are presented based on the IUCN redlist system for threatened species. Three of the species are Critically Endangered as each of them has a very restricted distribution. The other three species are Vulnerable. There has been a long debate pertinent to the taxonomic placement of Dendrocousinsia. Until extensive phylogenetic studies are performed within the Hippomaneae we propose to maintain this group as a distinct genus and not as a section within Sebastiania. This study highlights Dendrocousinsia as restricted to Jamaica with a high conservation priority because of its uniqueness and the Critically Endangered status of half of its species.

Pscheidt, A.C., H.-J. Esser & I. Cordeiro (2017). A new species of Microstachys (Euphorbiaceae, Hippomaneae) in Paraguay. Candollea 72: 27–30. In English, English and Spanish abstracts. A new species, Microstachys dasycarpa Pscheidt, Esser & Cordeiro (Euphorbiaceae, Hippomaneae), endemic to Paraguayan Chaco, is described and illustrated. The genus Microstachys A. Juss. is represented in this area by other three species : Microstachys corniculata (Vahl) Griseb., Microstachys hispida (Mart.) Govaerts and Microstachys serrulata (Mart.) Mull. Arg., with which this new species is compared.

Dendrothrix condorensis K.Wurdack, sp. nov. from the sub-Andean cordilleras of Ecuador and Peru is described and illustrated. The new species is geographically widely separated from its likely closest relative, D. yutajensis, which is endemic to the Guiana Shield region of southern Venezuela and adjacent Brazil, and notably differs in leaf morphology. Vegetative (i.e., epidermal micropapillae, trichomes) and reproductive (i.e., cymule glands, flowers, pollen) micromorphological features were examined with SEM. Rare tristaminate flowers were documented among the typical bistaminate ones. Seeds and diagnostic features among the four species of Dendrothrix are compared.

Although Stillingia loranthacea has commonly been considered a synonym of Stillingia saxatilis, it is reinstated to specific status in the present study. Stillingia loranthacea differs from S. saxatilis due to its orange-brown to dark brown bark, leaves sessile to subsessile (up to 4 mm long), obovate to elliptic-obovate with apex obtuse to rounded, base attenuate to decurrent, venation brochidodromous, and glands scutelliform. Both species are described and illustrated herein, including observations on habitat and conservation status, a map of distribution, a key, and a table containing distinctive characters. A lectotype is chosen for S. loranthacea.

Pollen morphology of 20 species of Euphorbioideae and one from Crotonoideae was examined with light, scanning and transmission electron microscopy. The pollen morphology presented here did not support the monophyly of Euphorbioideae, and the unique characters of tribe Stomatocalyceae such as absence of aperture margins, and thick and continuous endexine suggest the exclusion of Stomatocalyceae from Euphorbioideae which is in accordance with previous phylogenetic studies and wood anatomical data. Aforementioned pollen features in this tribe support that it is closely related to Acalyphoideae. Two subtribes of Stomatocalyceae were well recognized in terms of pollen morphology: Hamilcoinae includes species with reticulate or microreticulate exine patterns, and Stomatocalycinae includes those with perforate patterns with small supratectal elements. Three subtribes of Euphorbieae, classified in terms of pollen morphology, were further divided into three different types including perforate in Euphorbiinae, microreticulate in Neoguillauminiinae and reticulate in Anthosteminae, strongly supporting the Webster`s subtribal system. Hureae and Hippomaneae, having perforate sculpturing pattern with smooth margo, were similar in pollen morphology. Especially, the presence of small supratectal elements in Hura crepitans pollen suggests the close relationships with Excoecaria species of tribe Hippomaneae. According to the previous studies, unique intine thickness along the aperture margin in Euphorbieae was not reported elsewhere in Euphorbiaceae. However, in this study we found the same intine thickness along the aperture margin in Maprounea brasiliensis and Hura crepitans. We hypothesize that the similar intine thicknesses found in Euphorbieae and above two species are the evidence of close relationships among them.

Esser H.-J., Araujo Lucena M. F. de & Alves M.: A new species of Gymnanthes (Euphorbiaceae) from northeastern Brazil. — Willdenowia 40: 345–349. — Online ISSN 1868-6397; © 2010 BGBM Berlin-Dahlem. doi:10.3372/wi.40.40213 (available via http://dx.doi.org/) Gymnanthes boticario, a new species of Gymnanthes sensu lato (formerly Sebastiania sect. Adenogyne), is described from the caatinga forests of northeastern Brazil. A key to the pubescent-fruited species of Gymnanthes sensu lato and related taxa is provided.

The genus Gymnanthes Swartz (1788: 6, 95), originally considered as Neotropical (Pax & Hoffmann 1912), has recently been expanded to include species from Africa and Asia (Esser 1999, 2001). Previously, the two African species had been included in the separate genus Duvigneaudia Léonard (1959: 15), and were as such revised by Kruijt & Roebers (1996). Léonard (1959) had described the genus because these species were clearly distinct from all other African genera, but he did not compare any Neotropical plants, much like Kruijt & Roebers (1996). Also the World Checklist of Euphorbiaceae (Govaerts et al. 2000) accepted the genus as distinct. However, the African species hardly differ from many species of Neotropical Gymnanthes by any significant characters of the leaves and flowers, and although they have somewhat larger fruits, this does not seem to be sufficient to uphold Duvigneaudia as a separate genus. Therefore both genera were united by Esser (1999, 2001). Within Neotropical Gymnanthes, Duvigneaudia is most similar to the former genus Sarothrostachys Klotzsch (1841) from Brazil.

Phylogenetic relationships within Euphorbiinae were inferred from our analysis of the 3′; end of the chloroplast gene ndhF. A sampling of that subtribe covered 88 species; 3 closely related species from the subtribes Anthosteminae and Neoguillauminiinae and the tiribe Hippomaneae were included as outgroups. A phylogenetic assessment was carried out using the parsimony approach. The relationships revealed via these ndhF data supported the monophyly of subg.Esula, subg.Chamaesyce, subg.Euphorbia, and subg.Lacanthis. However, the polyphyly of subg.Agaloma, subg.Lyciopsis, and subg.Eremophyton also was strongly suggested. The African succulent Euphorbiinae can be divided into primarily two independent groups: 1) spiny succulents, which form a strongly supported clade with three subclades (subg.Euphorbia, subg.Lacanthis, andMonadenium+Synadenium); and 2) non-spiny succulents, which consist of sect.Meleuphorbia, sect.Medusae, sect.Anthacantha, sect.Trichadenia, sect.Pseudeuphorbium, sect.Treisia, and sect.Pseudacalypha. In the ndhF tree, the subg.Esula clade is placed as a sister to the rest of the Euphorbiinae. Thus, the origin of theEuphorbia s.I. should be sought within the herbaceous species of subg.Esula. The core North American endemicEuphorbia groups --Agaloma, Chamaesyce, andPoinsettia — are monophyletic and independent of the South American subg.Agaloma. Instead, they are derived from the AfricanEuphorbia subg.Lyciopsis andEremophyton. The Eurasian subg.Esula clade forms two subclades, which are concordant to sect.Esula and sect.Tithymalus.

The new combination Sebastiania integra is proposed based on the basionym Gymnanthes integra. Lectotypifications of four names of Sebastiania, occurring in Mexico, Central America, and Antilles, are proposed. A key to the species and a list of names excluded from the genus referred to the region are provided.

Stillingia (Euphorbiaceae) contains ca. 30 species from Latin America, the southern United States, and various islands in the tropical Pacific and in the Indian Ocean. We report here for the first time the occurrence of a member of the genus in China, Stillingia lineata subsp. pacifica. The distribution of the genus in China is apparently narrow, known only from Pingzhou and Wanzhou Islands of the Wanshan Archipelago in the South China Sea, which is close to the Pearl River estuary. This study updates our knowledge on the geographic distribution of the genus, and provides new palynological data as well.

A nomenclatural update is presented for the (hitherto monotypic) genus Pleradenophora . New combinations are presented for Pleradenophora bilocularis , P. lottiae , P. membranifolia , P. tikalana and P. tuerckheimiana (based on Sebastiania bilocularis , S. lottiae , S. membranifolia , S. tikalana and Sapium tuerckheimianum ), and four new synonyms are proposed. A key to the species is provided. The genus currently comprises five species, distributed from theUnited States toBolivia, with the highest diversity inMexico andGuatemala.

In this manuscript two new synonyms for Stillingia species are proposed. Stillingia dusenii is synonymized with Stillingia bodenbenderi, and Stillingia pietatis is synonymized united with Stillingia acutifolia. In addition, the lectotypes are proposed for 26 names.

The tribe Hippomaneae (Euphorbiaceae) in Brazil. The tribe Hippomaneae is discussed with respect to its taxonomic history, its placement within the Euphorbiaceae, its diagnostic characters (particularly the floral buds), current data on phylogeny and subdivision, and its general pattern of diversity. The tribe is represented in Brazil with 13 genera and ca. 120 species. A key to the Brazilian genera is provided. All Brazilian genera are discussed, citing relevant characters, recent taxonomic literature, and the current state of knowledge, sometimes pointing to unresolved problems. For five of the genera, published revisions exist; six genera have unpublished but completed revisions or are currently under revision. Actinostemon and Gymnanthes are currently the most difficult genera, mostly based on the absence of available up-to-date taxonomic references. For Mabea and Senefeldera, two genera with completed but currently unpublished revisions, additional data are given on aspects of their taxonomy, ecology and biogeography. A tribo Hippomaneae é discutida em relação à sua história taxonômica, posição sistemática nas Euphorbiaceae, em seus principais caracteres morfológicos diagnósticos, com ênfase no botão floral, em sua atual filogenia e subdivisão, e em seus padrões gerais de diversidade. A tribo está representada no Brasil por 13 gêneros e cerca de 120 espécies. Uma chave para os gêneros brasileiros é fornecida. Todos os gêneros do Brasil são discutidos sucintamente, citando-se suas características mais relevantes, a literatura taxonômica mais recente e o seu estado atual de conhecimento, bem como algumas sugestões para problemas ainda não resolvidos sobre os táxons. Há revisões publicadas para cinco dos gêneros, sendo que seis já foram revisados ou estão sendo revisados, mas permanecem inéditos. Actinostemon e Gymnanthes são atualmente os gêneros mais difíceis, especialmente pela ausência de referências taxonômicas atuais disponíveis. Para Mabea e Senefeldera, gêneros já revisados, mas não publicados, são fornecidos dados adicionais sobre a taxonomia, ecologia e biogeografia.

O estudo foi baseado na análise morfológica de espécimes de herbários nacionais e provenientes de coletas. A tribo está representada no Estado por oito gêneros: Actinostemon Sw. (3 spp.), Mabea Aubl. (1sp.), Maprounea Aubl. (1sp.), Microstachys A. Juss.(2 spp.), Sapium P.Browne (2 spp.), Sebastiania Spreng. (1sp.), Senefeldera Mart. (1sp.) e Stillingia Garden ex L. (1sp.). Os gêneros com maior distribuição no Estado são Maprounea, Sapium e Sebastiania, ocorrendo em todas as zonas fitogeográficas. Actinostemon, Mabea e Senefeldera sao restritos a floresta atlantica. São apresentadas chaves para identificação dos gêneros e espécies, descrições, comentários e ilustrações. The study was based on morphological analysis of specimens from various national herbaria as well as collected material. The tribe is represented in the study area by eight genera: Actinostemon Sw. (3 spp.), Mabea Aubl. (1sp.), Maprounea Aubl. (1sp.), Microstachys A. Juss.(2), Sapium P. Browne (2 spp.), Sebastiania Spreng. (1 spp.), Senefeldera Mart. (1sp.) and Stillingia Garden ex L. (1sp.). Widely distributed genera are Sapium and Sebastiania occurring in all phytogeographical zones. Actinostemon, Senefeldera and Mabea are restricted to the Atlantic rainforest. Identification keys to genera and species, descriptions, illustrations and taxonomic comments are presented.

The monotypic genus Glyphostylus (Euphorbiaceae) is compared with Excoecaria, and it is concluded that both genera are not distinct. Glyphustylus, instead, exhibits all characters diagnostical for Excoecaria. Gl.vphostylus laoticus is considered as a species of Excoeearia. and the necessary combination is made.

Gymnanthes klotzschiana is one of the most problematic species of its genus, not only from a morphological point of view, but also concerning its nomenclature. From among its syntypes, we propose herein the lectotypification of the name. Additionally, studies of herbarium material of Actinostemon unciformis and G. klotzschiana, including type and historical collections, have shown that they are conspecific. The second name has priority over the first. These considerations are part of an ongoing review of Gymnanthes.

Botanists estimate that 80 to 90% of existing plant species have already been described and it is expected that most undescribed species are rare or narrow endemic ones. Here we map the geographical distribution of Gymnanthes boticario, a species described in 2010, and show that the species is not only widespread, but was well-collected in the Caatinga semiarid vegetation prior to its description. During a revision of the genus Gymnanthes we also found collections of G. boticario in the Brazilian Mato Grosso do Sul state (in Pantanal ecoregion), in Paraguay (in Cerro Léon dry forests) and in Bolivia (in Chiquitano dry forest ecoregion) in a pattern that closely resembles the Pleistocenic Arc Hypothesis. We map the continental distribution of G. boticario, report the first records of it for Bolivia, Paraguay and the Brazilian Pantanal and show the rich data available in herbaria for a plant only recently described.

Microstachys nana and M. ditassoides subsp. villosa , two new taxa endemic to Brazil, are described, illustrated and compared with related species. Microstachys nana is closely related to M. glandulosa and is distinguished by its herbaceous habit, glabrous to glabrescent branches, pedicellate pistillate flowers, ovary with developed appendages, and inflorescences with spaced flowers. Microstachys ditassoides subsp. villosa is related to M. ditassoides subsp. ditassoides , from which differs by its densely villous branches, leaves with flat and sparsely serrate margins, oblong-obovate staminate sepals obtuse at the apex, and externally glabrous pistillate sepals with cylindrical lateral-basal glands. Two new combinations are proposed: Microstachys glandulosa is based on Cnemidostachys glandulosa , a Brazilian species with broadly elliptic to orbicular, pubescent leaves and marginal glands situated in small lateral lobes; Microstachys stipulacea is based on Gymnanthes stipulacea , as a glabrous species unusual for its long petioles and stipules and broadly elliptic to suborbicular leaves, and known from the border region between Brazil and Uruguay.

The monophyly and phylogenetic relationships of the tribe Euphorbieae (Euphorbiaceae) were evaluated using separate weighted maximum parsimony analyses of nucleotide sequences of the nrDNA internal transcribed spacer (ITS) region and cpDNA coding region ndhF. The study included 223 ingroup species representing nearly all of the previously recognized genera, subgenera, and sections within the Euphorbieae and 4 outgroup taxa from the tribe Hippomaneae (Euphorbiaceae). Both the ITS and ndhF analyses support the monophyly of Euphorbieae in addition to the monophyly of its three subtribes, Anthosteminae, Neoguillauminiinae, and Euphorbiinae. Within Euphorbiinae, there are four major clades, only one of which corresponds with a previously recognized taxon; the three remaining clades are conglomerates of various subgenera and sections. The majority of the subtribe is composed of a paraphyletic Euphorbia. All other genera currently recognized in the subtribe are nested within Euphorbia. In addition, Synadenium and Endadenium are nested within Monadenium. Within Euphorbia, the majority of the currently recognized subgenera are either paraphyletic or polyphyletic. Biogeographical patterns examined in light of the molecular evidence suggest that the tribe Euphorbieae arose in Africa, possibly before the breakup of Gondwanaland, at which time the major lineages of subtribe Euphorbiinae were already present. It is argued that the best solution for Euphorbia classification is a broad circumscription of Euphorbia that contains all of the about 2000 species of the subtribe Euphorbiinae.

The new genusRhodothyrsus is proposed, based on the AmazonianSenefeldera macrophylla Ducke but also containing another newly described species,Rhodothyrsus hirsutus from northwestern Venezuela. The genus is a member of the tribe Hippomaneae of the Euphorbiaceae and apparently related toSenefeldera, but its closest relationships are still obscure, because the phylogeny of the tribe is poorly known and most of the significant characters ofRhodothyrsus are probably autapomorphies or symplesiomorphies. The restriction to tropical lowland rain forests is rare within the Hippomaneae, and several floral characters, pointing to a specialized pollination possibly by butterflies, are unique in the tribe.

A key to and some remarks on Maprounea in the Neotropics are presented. Maprounea guianensis var. obtusata is discussed and raised to specific rank with the new name Maprounea amazonica. Maprounea brasiliensis is accepted as distinct from M. guianensis. The taxa are separated mainly by characters of the leaves and by fruit size. Additionally, Maprounia glauca is established as a new synonym of Mabea taquari, and a lectotype is designated for the latter. Maprounea Aublet (Euphorbiaceae, Hippomaneae) is a small genus of shrubs and trees occurring in the Neotropics and in Africa. Although the South American taxa have been treated twice quite recently, their taxonomy is still not fully resolved. Pax and Hoffmann (1912) accepted two neotropical species, Maprounea guianensis Aublet and M. brasiliensis A. Saint-Hilaire, both without infraspecific taxa. Allem (1976), however, considered these two species to be identical and united them under the older name, M. guianensis. Senna (1984) disagreed with him and accepted both species as well as a number of varieties of M. guianensis, with the exception of M. guianensis var. undulata Muller Argoviensis, which she did not consider to be distinct from the typical variety. Allem's (1976) study was based mainly on plants from central Brazil and concentrated on floral characters, neglecting the varieties described from other regions. The revision of Senna (1984) was uncritical, although it included very detailed illustrations of all taxa. From these illustrations it is quite obvious that the leaves of M. guianensis var. obtusata (Muller Argoviensis) Muller Argoviensis are very different from those of all other neotropical taxa of the genus. On further examination of leaf and fruit characters in particular I now conclude that this variety represents a distinct species, and also that M. brasiliensis should be kept separate from M. guianensis. KEY TO THE NEOTROPICAL SPECIES OF MAPROUNEA la. Leaves apically obtuse to rounded to emarginate, abaxially eglandular at base (Fig. 1A); 0-1 pistillate flower per inflorescence; staminate inflorescence at least as wide as long; fruits 8--10 mm long M. amazonica lb. Leaves apically acute to mucronate to acuminate, rarely obtuse, abaxially often with basal glands, rarely without; (0-)2-3 pistillate flowers per inflorescence; staminate inflorescence longer than wide; fruits 4-10 mm long. 2a. Tree up to 25 m tall; leaves distinctly longer than wide, apically acute to acuminate, abaxially with 0-1(-2) pair(s) of base glands (Fig. 1F), often with additional submarginal glands in upper half; fruits 4-6(-8) mm long . M. guianensis 2b. Shrub up to 1.5 m tall; leaves hardly longer than wide, apically mucronate, rarely obtuse, abaxially usually with 2-4 pairs of basal glands (Fig. 1G), eglandular in upper half; fruits 8-10 mm long........ M. brasiliensis Maprounea amazonica Esser, nom. et stat. nov. Replaced name: Maprounea guianensis Aublet var. guianensis forma obtusata MUller Argoviensis, Linnaea 32: 115. 1863. Maprounea guianensis Aublet var. obtusata (MUiller Argoviensis) Muller Argoviensis, in Martius, Fl. Bras. 11.2: 543. 1874. TYPE: Brazil. Amazonas: Barra (= Manaus), igap6 of an igarap6, May 1851, Spruce 1475 (lectotype, selected here, G-DC not seen, microfiche; isolectotypes, BM, BR, E, GH, K, NY, OXF, P, TCD). Figure 1A-E. The name Maprounea obtusa Pax already exists for an African species. A new combination based on the neotropical variety obtusata would be very similar to the African name, and because of the risk of confusion a new name, M. amazonica, was chosen according to Article 53.3 of the International Code of Botanical Nomenclature (Greuter et al., 1994). Shrub or tree up to 12 m tall and 15 cm stem diam. Bark smooth. Totally glabrous. Monoecious. Stipules broadly elliptic, ca. 0.7-0.9 x 0.5-0.9 NovoN 9: 32-35. 1999. This content downloaded from 157.55.39.78 on Mon, 20 Jun 2016 07:31:39 UTC All use subject to http://about.jstor.org/terms Volume 9, Number 1 1999 Esser Neotropical Maprounea 33

Omphalea ankaranensis, a shrub endemic to limestone karst hills of northern Madagascar, is described and illustrated. The species is closely related to Omphalea palmata Leandri of western Madagascar but differs in its entire to coarsely crenate-dentate leaf blade margins, broader inflorescence bracts, lax cymules, and shorter pistillate flower pedicels. The new combination Omphalea oppositifolia (Willdenow) L. J. Gillespie is made for the widely distributed rainforest species of eastern Madagascar, previously known as Omphalea biglandulosa Persoon. A synopsis including new lectotypifications and a key to the four Madagascan species of Omphalea is provided. Omphalea L. is a genus of ca. 17 species belonging to the Euphorbiaceae. Six species are canopy lianas, while the remaining species range in habit from shrubs to large canopy trees. The genus is known from the Neotropics, southeast Asia to northeast Australia, Tanzania, and Madagascar, with centers of diversity and endemism in the Caribbean (6 species, 5 endemic) and in Madagascar (4 species, all endemic). While several species are widespread, the majority have limited ranges and some are quite rare. Species occupy a diversity of habitats from lowland rainforest, wet montane forest, to dry forest and thicket on limestone and sandy soils. The genus is characterized by an androecium of two or three stamens with connate filaments, styles that are completely fused into a usually massive stylar column, large foliaceous inflorescence bracts, and a complex inflorescence architecture. Inflorescences are technically thyrses and consist of spicate, racemose, or paniculate main axes that bear numerous cymules. These cymose units may be glomerate to lax and each is subtended by a usually foliaceous bract (note that bracteoles are defined as subtending axes within a cymose unit). Other features common in the genus but rarely found elsewhere in the family include red latex, liana habit with tendril-like climbing stems, mushroom-shaped androecia, and large fruits. Omphalea has long been considered a well-defi ed genus and one that is rather isolated in the Euphorbiaceae. The genus has been allied with genera that belong to all three uniovulate subfamilies in Webster's classification (1975, 1994). In the past Omphalea was usually placed in either tribe Hippomaneae (Baillon, 1858, as tribe Excaecarieae; Pax & Hoffmann, 1912), which is included in Webster's subfamily Euphorbioideae, or tribe Gelonieae (Mueller, 1866; Pax & Hoffmann, 1931; Hutchinson, 1969), a heterogeneous grouping of genera belonging to all three uniovulate subfamilies. More recently, Webster (1994) treated the genus as the monogeneric tribe Omphaleae, close to tribe Plukenetieae in subfamily Acalyphoideae. In contrast, Airy Shaw (1980) included the genus in his tribe Jatropheae (which comprises genera placed by Webster in subfamily Crotonoideae) in his tentative scheme for natural grouping of genera. Recent preliminary evidence from molecular and specialist herbivore phylogenetic studies appears to support a relationship with members of subfamily Crotonoideae (Wurdack & Chase, 1996; Lees & Smith, 1991). Its isolated position and unusual combination of plesiomorphic (e.g., extrastaminal disc, imbricate staminate sepals) and derived (e.g., presence of laticifers, foliaceous bracts, few connate stamens, entirely connate styles) character states suggest that Omphalea may represent a relatively early evolutionary branch within the uniovulate euphorbs (Gillespie, 1988b), perhaps near the base of subfamily Crotonoideae. Three species of Omphalea were previously known from Madagascar. The east coast rainforest tree 0. oppositifolia (Willdenow) L. J. Gillespie was first collected, illustrated, and described as the genus Hecatea by Du Petit-Thouars (1804a, 1804b, 1805) and formally named as a species by Willdenow (1805) in the early 1800s. Much later, Leandri (1938) described two dry forest species, 0. occidentalis and 0. palmata, from the west coast of Madagascar. A fourth species was recently discovered by the author on limestone karst in the Reserve Speciale Ankarana in northern Madagascar. A specimen of this new species from Montagne des NovoN 7: 127-136. 1997. This content downloaded from 207.46.13.112 on Mon, 03 Oct 2016 04:55:17 UTC All use subject to http://about.jstor.org/terms

The Euphorbieae and Hippomaneae, though both usually placed in subfamily Euphorbioideae, differ in many inflorescence details and can be linked unambiguously only by one cryptic character: the rod-shaped starch grains in the latex. While the Hippomaneae have inflorescences very similar to those of many other members of the Euphorbiaceae, the Euphorbieae have an inflorescence so specialized that one seems to be forced to relate it to other members of the family througb a hypothetical ancestor with a synflorescence of axillary bisexual cymes more primitive than most extant taxa possiblv other thari Jatropha.

The new genus Dendrothrix is proposed. Two of its species are new to science, the third one was originally allied to Sapium. Keys for distinguishing related genera using flowers, fruits, and leaves are provided, as is a key to the species of Dendrothrix. A taxonomic revision of the subtribe Mabeinae Pax & K. Hoffmann of the Euphorbiaceae (tribe Hippomaneae A. Jussieu ex Spach) has necessitated the establishment of a new genus in order to accommodate species that have confused students of the Euphorbiaceae for some time. The three species are known from northern Brazil and Venezuela. Dendrothrix Esser, gen. nov. TYPE: Dendrothrix yutajensis (Jablonski) Esser. A ceteris generibus tribus Hippomanearum differt pilis ramosis, foliis integris subtus papillis obtectis sine glandulis marginalibus praeter bases glandulosas, thyrsis regulatim plerumque semel ramosis, glandulis bractearum disciformibus vel cyathiformibus, floribus masculinis bistaminalibus cum filamentis tota longitudine connatis, ovariis pubescentibus, et mericarpiorum septis filo vasculari furcato vel duplici instructis. Trees or shrubs. Hairs multicellular and ramified. Leaves alternate, simple, coriaceous, entire; abaxial epidermis minutely but densely papillose; without petiolar, submarginal, or marginal glands but abaxially with a pair of basimarginal glands and sometimes with laminar glands of 0.2-0.35 mm diam.; petioles 1.5-5.5 cm long. Stipules very small to absent. Thyrses yellowish to cream-colored, terminal, always compound, mostly with one order of branching with several lateral thyrses, bracts small, scaly, glandless. Male cymules distal, at least 8-flowered, their bracts carrying basal glands which, when dry, are cup-shaped or disc-shaped and ? 1 mm long; bracteoles absent. Staminate flowers sessile, at anthesis with 0.6-1.0-mm-long pedicel, subtended by a two-parted calyx fused for most of its length; stamens two per flower, connate, lateral flowers often unistaminate; anthers 0.4 mm long, filaments at anthesis slightly longer than anthers. Female flowers proximal, bracteolate, shortly pedicellate, tricarpellate; sepals three, partly fused; ovary pubescent; style short but evident. Fruit a septicidal schizocarp, smooth, with scattered, caducous pubescence, glabrescent, up to 6 mm long. Mericarps bearing one bifurcate or two distinct vascular strands visible on each septum, leaving an inconspicuous alate central columella. Seeds dry, brown, smooth, carunculate in two species (not known in D. multiglandulosa). The name of the genus refers to the treelike branched hairs, which are unusual for the Euphorbiaceae. This genus differs from the other three neotropical genera of the Hippomaneae with compound thyrses in both its bistaminate male flowers and its totally fused filaments. The inflorescence is similar to that of Senefelderopsis Steyermark: the thyrses are of the same size and are strictly terminal. A single, and rarely a second, order of branches occur, always subtended by small scaly bracts, and the staminate cymules are many-flowered. The two genera therefore can be confused superficially. However, the hairs of Senefelderopsis are multicellular but unbranched, the bracteal glands of its two species are always cylindrical when dry, the staminate flowers carry persistent bracteoles, and its fruits are larger (length 15-25 mm) and have a leathery outer layer. Additionally, the leaves of Senefelderopsis exhibit a row of abaxial submarginal glands and a pair of adaxial basal glands. The hairs and fruits of Dendrothrix are very similar to those of Mabea Aublet. The leaf glands of Mabea, however, are strictly marginal or submarginal, never laminar. The lateral secondary thyrses of Mabea occur irregularly (they are missing in many species, whereas in others they can be several times compound), and the staminate cymules are mostly 3-flowered. The calyx of pistillate flowers and fruits consists of six sepals. Mabea always shows a single undivided vascular strand on each septum of the mericarps, the length of the capsules always exceeds 8 mm, and its indumentum is very dense and persistent. Senefeldera C. Martius, the third other genus with compound thyrses, is quite different, e.g., it NOVON 3: 245-251. 1993. This content downloaded from 157.55.39.215 on Wed, 31 Aug 2016 04:14:05 UTC All use subject to http://about.jstor.org/terms

Inflorescences from the Claiborne Formation of western Tennessee are remarkably similar to those of the tribe Hippomaneae, subfamily Euphorbioideae, of the Euphorbiaceae. The fossil inflorescences are spikes of bract-subtended cymules of at least three florets each. Florets are composed of at least three stamens. Palynological features of the fossils are also shared by the Hippomaneae. Fossil pollen is tricolporate, prolate (26.9 x 20.6 ,um; P/E = 1.3), with lalongate pores. Exine structure is tectate columellate with a perforate tectum. The exine is reticulate and the muri are conspicuously striate. These specimens represent the first fossil floral evidence of the Euphorbiaceae. It is surprising that inflorescences of the Hippomaneae so modern in aspect existed in the Middle Eocene, since the tribe is universally considered to be one of the most advanced in the family.

Pollen nuclear number is determined in 139 species of 5 genera in the Euphorbieae, subtribe Euphorbiinae. The 111 new determinations are tabulated along with previous reports, and the results indicate that the distribution of binucleate (II) and trinucleate (III) pollen is strongly associated with the taxonomic groupings within the Euphorbieae. Although binucleate pollen is probably primitive within the tribe Euphorbieae, as suggested by the nuclear condition in Neoguillauminia, the situation in Euphorbia still requires further elucidation. Within Euphorbia, the morphologically most primitive species studied have III pollen despite the fact that II pollen is presumably the original condition for the subtribe Euphorbiinae. In Euphorbia, II pollen only is reported from nine sections and III pollen only from ten sections, while in four sections (Esula, Goniostema, Aphyllis, and Deuterocalli) both II and III pollen have been found. The New World species of Euphorbia nearly all have III pollen, whereas the vast majority of the African succulents have II pollen. The genera of New World origin, Chamaesyce and Pedilanthus, have III pollen, while the African genera Monadenium and Synadenium have II pollen. Independent derivations of III pollen from II pollen appear to have occurred in sections Goniostema, Aphyllis, and Deuterocalli (all of subg. Euphorbia). There is no evidence that reversals from III to II pollen have occurred. IN HIS SURVEY of pollen nuclear number in the angiosperms, Brewbaker (1967) indicated that the Euphorbiaceae were one of 32 families in which both binucleate (II) and trinucleate (III) pollen grains occur; at the same time, he noted that Euphorbia is one of only five angiosperm genera in which both II and III pollen have been recorded. Webster and Rupert (1973) reported pollen nuclear numbers in 66 species of Euphorbiaceae belonging to 42 genera, and confirmed the results of Brewbaker. In the tabulation of Webster and Rupert, 18 tribes were shown to have II pollen, three to have III pollen, while in three tribes both II and III pollen were recorded. With the somewhat dubious exception of the Australian tribe Ricinocarpeae (which requires further study), the mixed records of II and III pollen are restricted to the subfamily Euphorbioideae (s. str. of Webster, 1975), specifically to the two tribes Hippomaneae and Euphorbieae. Pollen nuclear numbers were reported by Webster and Rupert (1973) only for seven species in six genera of tribe Euphorbieae. Reports on nuclear number made up to that

The taxa of the Euphorbiaceous tribe Hippomaneae (sensu Webster, 1975) still present notoriously difficult problems in generic delimitation, despite the revisionary efforts of Mueller (1866), Baillon (1874), Bentham (1880), Pax and Hoffmann (1912), and others. This is especially true of the complex of taxa with highly reduced flowers which Baillon (1874) reduced to the single genus Excoecaria. Although Rogers (1951) achieved an acceptable differentiation between Sapium and Stillingia, the demarcation lines between Actinostemon, Gymnanthes, Sebastiania, and some smaller genera remain uncertain. This problem in classification is exacerbated by some nomenclatural difficulties, among which the status of Gymnanthes is most critical. Rothmaler (1944) initiated a still unresolved nomenclatural crisis by resurrecting the generic name Ateramnus P. Browne (1756), based on a Jamaican plant that Rothmaler identified with Gymnanthes lucida Sw. Since Ateramnus is a validly published earlier name, Rothmaler argued that it should be adapted for the genus currently known as Gymnanthes Sw. (1788). Recently, this suggestion of Rothmaler's has been taken up by Adams (1970, 1972) and by Gillis (1974), who apply names under Ateramnus to species heretofore treated under Gymnanthes. Gillis avowedly follows the lead of Dandy (1967), who in his index of generic names published between 1753 and 1774 listed Ateramnus in such a manner as to imply that it has priority over Gymnanthes. This has created a confusing situation in the current literature, because some botanists have followed Adams and Gillis in adopting Ateramnus (Correll, 1979; Tomlinson, 1980), whereas others continue to use Gymnanthes (Foumet, 1978; Elias, 1980). Little (1979), in his most recent index to the names of North American trees, judiciously declines to accept Ateramnus in place of Gymnanthes until this nomenclatural conflict is resolved. One solution to this problem might be to propose Gymnanthes for conservation. However, as noted by Gillis (1974), conservation of Swartz's generic name has already been rejected once by the Special Committee for Pteridophyta and Phanerogamae (Taxon 3: 241. 1954). The deciding factor in that vote may have been doubt that Ateramnus and Gymnanthes are synonyms. Long before Rothmaler's article, Hallier (1918) concluded that it is highly doubtful that Ateramnus was based on the plant Swartz called Gymnanthes lucida. This may be seen clearly by comparing the characteristics of Swartz's species with the brief description of Browne (1756: 339)

In 1961, R. McVaugh conclusively showed that Sereno Watson's Mexican genus Corythea, erroneously placed in the Tribe Hippomaneae by its authora course which was followed by Pax (I912)-is in fact referable to Acalypha (Tribe Acalypheae). Two species had been described in Corythea, namely C. filipes S. Wats., upon which the genus was founded in 1887, and C. multiflora Standl., also from Mexico, in 1923. McVaugh, at the same time as combining C. filipes under Acalypha, also reduced C. multiflora into synonymy with it. However, I have now examined the type-material of both species which is deposited in the Gray Herbarium (GH) and in the Smithsonian Institution (US), and have come to the conclusion that Standley was correct in regarding the type of C. multiflora as being specifically distinct from C.filipes. The leaves of the former are broadly ovate and long-petiolate, whilst those of the latter are narrowly elliptic-ovate and shortly petiolate, and the female inflorescence of C. multiflora is many-flowered, as the epithet indicates, whilst that of C. filipes is only I-2-flowered. C. multiflora has only been collected once since the type collection, and that was by McVaugh himself. The details of this gathering are:-Mexico, Nayarit, 3-2 km SE. of Las Varas, road to Mazatin, 60-90 m, 12 Jul. 1957, McVaugh 15354 (US!). A new combination is required for Standley's species under Acalypha

The Eocene sediments of southern Maryland and adjacent Virginia have yielded multilocular fruits assignable to the extinct generaWetherellia Bowerbank andPalaeowetherellia Chandler. This is the first report of their co-occurrence in one deposit.Wetherellia has previously been reported from the Eocene of southern England and West Germany (two species), whilePalaeowetherellia has been reported from the Eocene and possibly latest Cretaceous of Egypt (one species). APalaeowetherellia-like fruit has been reported from the Eocene of southeastern North America.Wetherellia marylandica comb. nov. andPalaeowetherellia species are described; new information is provided for the previously established speciesWetherellia variabilis andW. dixonii. The familial assignment of both genera is reviewed.Palaeowetherellia is most similar to fruits of the tribe Hippomaneae of the Euphorbiaceae, whileWetherellia finds counterparts in the Euphorbiaceae and the Meliaceae. While the exact affinities ofWetherellia are difficult to resolve through comparison to modern fruits, the similarity ofWetherellia andPalaeowetherellia might suggest that the former is more likely euphorbiaceous than meliaceous. The discovery of these New World members of both genera reinforces the importance of floristic exchange across the North Atlantic in earliest Tertiary time.