A taxonomic revision of chamaecrista (caesalpinioideae, cassieae, cassiinae) in Southern Africa

Abstract

The southern African species of Chamaecrista were all treated under Cassia in Gordon-Gray’s treatment for the Flora of Southern Africa. However, given the subsequent generic recircumscriptions in the subtribe Cassiinae, and the expanded collections of these taxa, there is a need to revisit the taxonomy of the group. The present study aimed to conduct a detailed taxonomic revision of the species of Chamaecrista indigenous to the flora of southern Africa region. Extensive fieldwork was carried out to study the taxa in their natural environment and morphological characters were additionally studied using herbarium material. The revision presented here includes comprehensive descriptions, a key to the species, nomenclature, typifications, diagnostic characters with illustrations, and geographical distribution maps of all recognised taxa. Eleven species of Chamaecrista are recognised for the flora of southern Africa, two of which are described as new, i.e. Chamaecrista grandiglandulata and C. gordon-grayei. In addition, one new subspecies is described, namely C. gordon-grayei subsp. longipedicellata, while Chamaecrista comosa var. capriconia is raised to the rank of subspecies, viz. Chamaecrista comosa subsp. capriconia. The typifications published here include lectotypes designated for Chamaecrista plumosa and C. stricta, neotypes designated for C. capensis var. flavescens, C. comosa, and C. plumosa var. diffusa, and an isolectotype designated for C. stricta.