Flora of Distrito Federal, Brazil: Cassia, Chamaecrista p.p. and Senna (Leguminosae - Caesalpinioideae)

Abstract

This paper provides a survey of the species of the genus Cassia s.s., Senna and Chamaecrista (Leguminosae - "Caesalpinioideae") occurring in Distrito Federal (DF). This unit of the federation is entirely in the Cerrado, which is one of the "hotspots" for biodiversity conservation worldwide. Leguminosae is the third largest family of flowering plants in the world and the largest in Brazil, and also the greater economic importance after Poaceae. The family has traditionally been divided into three subfamilies: Faboideae, Mimosoideae and Caesalpinioideae, however, the last is not monophyletic. Caesalpinioideae is divided into four tribes: Cercidae, Detarieae, Caesalpinieae, and Cassieae, and this latter includes the subtribe Cassiinae that groups the three genres to be studied. The latest data on the Caesalpinioideae from Distrito Federal record two species of Cassia, 54 of Chamaecrista, and 18 of Senna. Chamaecrista species belonging to the section Absus have already been studied for DF, which is responsible for this work the other sections. The objective of this proposal is to contribute to the knowledge of the flora of the DF, with the development of a taxonomic treatment of Cassia, Senna and Chamaecrista. This work will provide descriptions, identification keys to genera and species, illustrated boards and maps of geographical distribution, according to the model adopted by the Flora of Distrito Federal.