Taxonomy and invasive potential of the Cassiinae in southern Africa (Caesalpinioideae, Fabaceae)

Abstract

Cassiinae is a large subtribe of the tribe Cassieae (Caesalpinioideae) that comprises ca. 700 species distributed throughout the Americas, Africa, Eurasia and Australia. The southern African species of Cassiinae (indigenous, naturalised and cultivated) were all treated under Cassia L. in Gordon-Gray’s (1977) treatment for the Flora of southern Africa. However, given the subsequent generic recircumscriptions in the subtribe and the expansion of collections of these taxa since, this treatment is now outdated. The aim of the present study was to provide an overview of the subtribe Cassiinae in southern Africa, assess the invasive potential of all naturalized species (viz. Cassia s.s., and Senna Mill.) and conduct a detailed taxonomic revision of the species of Chamaecrista (L.) Moench. indigenous to southern Africa.