Estudo taxonômico de >i<Senna>/i< sect. >i<Chamaefistula>/i< ser. >i<Bacillares>/i< (Bentham) H.S.Irwin & Barneby (Leguminosae Juss. - Caesalpinioideae DC.) do Brasil

Abstract

Taxonomic study of Senna sect. Chamaefistula ser. Bacillares (Bentham) H.S.Irwin & Barneby (Leguminosae Juss. -Caesalpinioideae DC.) in BrazilSenna (Leguminosae, Cassiinae) comprises ca. 350 species mainly distributed throughout the tropical and subtropical regions of Americas. In Brazil, the genus Senna comprises ca. 80 species, widely distributed throughout all the Brazilian domains and in almost all vegetation types. Although a speciose genus, a few studies have addressed Senna in recent years and its taxonomic knowledge is still deficient. Senna sect. Chamaefistula ser. Bacillares comprises ca. 50 species restricted to the Americas being found in a great diversity of habitats, being particularly rich in forest ecotones. Many species of series Bacillares remains poorly known by scientists and further taxonomic studies are required. In this sense, the present study comprises a taxonomic study of the species of Senna sect. Chamaefistula ser. Bacillares from Brazil. The present study was based on field expeditions to sample and observe the taxa in their habitat, and on the analysis of the Herbarium collections. The present thesis is organized in two chapters, the first one refers to the discovery and description of a new and endemic species from the Atlantic Forest of Bahia. The second chapter corresponds to a taxonomic synopsis comprising 24 species and 11 varieties native to Brazil, identification keys, taxonomic comments and distribution data for each taxon.