The genus Acosmium s.l. (Leguminosae: Papilionoideae) traditionally included up to 20 tree species mostly from South America. Due mainly to radial floral symmetry, the taxonomy of Acosmium has been historically confounded with four other Papilionoideae genera: Dicraeopetalum, Guianodendron,Leptolobium, and Sweetia. We used comprehensively sampled molecular data from the nuclear ribosomal internal transcribed spacer (ITS/5.8S) and two plastid DNA (matK, trnL intron) regions in order to evaluate the monophyly of Acosmium s.l. and to shed light on the relationships of its distinct lineages in the context of the Papilionoideae phylogeny. Parsimony and Bayesian analyses of all data concurred in resolving a polyphyletic Acosmium s.l. Our data agreed with previous molecular phylogenetic analyses that resolved Dicraeopetalum and Sweetia apart from Acosmium s.l. Unexpectedly, Acosmium s.str., thought to belong to the Genistoid clade, is here strongly resolved within the Dalbergioid Pterocarpus clade. Despite being classified until recently as different sections of Acosmium s.l., Leptolobium and Guianodendron were resolved within the Genistoid clade as part of a Bowdichia clade with the genera Diplotropis and Bowdichia. Our results reveal that radial floral symmetry has evolved independently in all Acosmium segregates and strongly suggest that the primacy given to floral characters involving corolla symmetry and petal differentiation in traditional legume classification has often obscured phylogenetic relationships.

The actual (A) and potential (Apot) photosynthetic rates of C3 and C4 tropical crop species grown under greenhouse conditions was compared. The following species were investigated: Oryza sativa, Phaseolus vulgaris, Glycine max, Helianthus annuus, Gossypium hirsutum, Manihot esculenta, Theobroma cacao, Coffea arabica, Hevea brasiliensis, and Eucalyptus urophylla × E. grandis, all from the C3 group, and Amaranthus sp., Panicum maximum, Pennisetum purpureum, Zea mays and Saccharum officinarum, from the C4 group. A, determined under non-limiting light at ambient temperature and CO2, was measured with an infrared gas analyser, whilst Apot, determined under saturating light and CO2 at an optimal temperature (35 ºC for all species), was gauged with a gas-phase oxygen electrode. On an area basis, A varied from 5.0 up to 26.3 mumol CO2 m-2 s-1, whilst Apot was very similar in 14 of the 15 species, with an average rate of 35.0 ± 2.4 mumol O2 m-2 s-1. The value of Apot in T. cacao was approximately half the mean of the remaining species. On a mass basis, variations in A were much larger, and differences in Apot, although not large, emerged. The overall mean Apot per unit mass in the four tree species was 28.0 ± 2.2 mumol O2 g-1 min-1 against 44.6 ± 5.8 mumol O2 g-1 min-1 in the remaining species. As a whole, the results evidenced a conservative behaviour of the photosynthetic apparatus to fix CO2 amongst the species investigated, despite the large differences in A among them.

Barneby são registradas pela primeira vez para a flora do Estado. São apresentadas chave analítica, descrições e ilustrações para as espécies. Além disso, são fornecidos dados sobre a distribuição geográfica, hábitat, nomes vulgares e importância econômica das espécies estudadas.Palavras-chave: Leguminosae, Caesalpinioideae, Senna, taxonomia, Rio Grande do Sul, Brasil ABSTRACT -(The genus Senna (Leguminosae, Caesalpinioideae) in Rio Grande do Sul State, Brazil). This paper presents a taxonomic study of the species of the genus Senna occurring in Rio Grande do Sul State, Southern Brazil. Nineteen species were found and the occurences of Senna aphylla (Cav.) H

RESUMO -(Diversidade de Leguminosae em uma área de savana estado de Roraima, Brasil). Leguminosae é considerada a família mais diversa nas savanas de Roraima, que são as maiores áreas de savana da Amazônia brasileira. Este trabalho tem como objetivos fornecer uma listagem fl orística e analisar os padrões de distribuição geográfi ca dos táxons de Leguminosae encontrados em uma área de savana em Boa Vista, Roraima (02º52´07´´N; 60º43´03´´W). Foram registrados 80 táxons distribuídos em 38 gêneros. Seis táxons são novos registros para a fl ora de Roraima. Os gêneros que apresentaram o maior número de espécies foram Aeschynomene e Chamaecrista, cada um com sete espécies. Leguminosae-Papilionoideae foi a subfamília mais diversa em número de gêneros (24) e de táxons infragenéricos (53). A análise da distribuição geográfi ca revelou a predominância de táxons com padrão neotropical. A área estudada representa um sítio diverso em táxons de Leguminosae, pois concentra cerca de 87% da diversidade citada para a família nas savanas de Roraima. Palavras-chave: fi togeografi a, Guayana, levantamento fl orístico, Leguminosae ABSTRACT -(Leguminosae diversity in a savanna area of Roraima, Brazil). Leguminosae is the most diverse family in the savannas of Roraima, which are the largest savanna areas in the Brazilian Amazon. This paper presents a fl oristic survey and an analysis of the geographic distribution patterns of Leguminosae taxa in a savanna area at Boa Vista, Roraima (02º52´07´´N; 60º43´03´´W). The survey identifi ed 80 taxa belonging to 38 genera. Six taxa are new records for the fl ora of Roraima. The best-represented genera were Aeschynomene and Chamaecrista, both with seven species each. LeguminosaePapilionoideae was the most diverse subfamily based on the number of genera (24) and infrageneric taxa (53). The phytogeographical analysis revealed predominance of taxa with a Neotropical distribution. The savanna site analyzed represents a legume diverse area, because it concentrates 87% of legume diversity referred for the savannas of Roraima.

Acosmium Schott is a Neotropical genus of ca. 17 species of trees with non-papilionoid, actinomorphic flowers. It has been included in the genistoid clade (Leguminosae, Papilionoideae) in recent phylogenetic analyses. A morphology-based cladistic analysis was performed to test the currently assumed monophyly of Acosmium, assess the validity of the infrageneric classification of Yakovlev, and detect synapomorphies and other diagnostic characters in Acosmium and related taxa. Thirty-four species representing ten genera of subfamily Papilionoideae were included in the analysis: all accepted species of the four sections of Acosmium together with species of Bowdichia, Clathrotropis, Diplotropis, Bolusanthus, Cadia, Poecilanthe, Cyclolobium, and Ormosia; two species of Luetzelburgia were selected as outgroups. The results do not support the monophyly of Acosmium; the species of this genus fall into three distinct, not closely related clades that correspond to the sections of Acosmium established by Yakovlev except for sect. Mesitis that merges into sect. Leptolobium. We propose: (1) recognizing a narrowly circumscribed genus Acosmium; (2) reinstating the generic name Leptolobium Vogel, encompassing sections Leptolobium and Mesitis; and (3) segregating A. praeclarum (Sandwith) Yakovlev into a new genus, Guianodendron. The phylogenetic relevance of some new or neglected characters, especially from bud architecture, seed, and seedling morphology is emphasized.