Аннотация:The papilionoid genus Stylosanthes Sw. includes about 50 spp. distributed world wide in the tropics, approximately half of them grow in South America.The present study focuses on South American Stylosanthes. Based on examinations of herbarium specimens, as well as field observations, a total of 25 taxa (23 spp. and 2 varieties) are here described and identified with a key. Most of the species have been found to be more widely distributed than expected from the previous taxonomic literature, and the genus appears to be mainly concentrated in Brazil and Paraguay. Stylosanthes leiocarpa Vogel is new to the flora of Argentina and the presence of S. nervosa J. F. Macbr. is confirmed in Argentina. The nomenclature of S. guianensis (Aubl.) Sw. is analyzed. Clarifications are made about nine recently described Brazilian species. The names S. hispida Rich. and S. longiseta Micheli are resurrected. Lectotypes or neotypes for eight species and 18 new synonyms are proposed.
