10. Mimosa L. (mimosa)

About 500 species, North America to South America, Caribbean Islands, Asia, Africa, Madagascar, most diverse in the New World tropics.

Traditionally, most authors have treated the Missouri species of Mimosa as part of the segregate genus Schrankia Willd. Schrankia was circumscribed to include about 15 or more species native from the central and southeastern United States to South America (Isely, 1971, 1973) and introduced sporadically in the Old World tropics. These were categorized as mostly prickly herbaceous plants with 4-angled legumes that appear to dehisce by 4 sutures. Since the time that Schrankia was described, many additional species of Mimosa have been described, and all of the characters that define this segregate also are found in other groups of Mimosa species. In his worldwide monograph of the group, Barneby (1991) chose to treat Schrankia as Mimosa section Batocaulon DC. series Quadrivalves Barneby. He further chose to reduce all of the species of Schrankia to a complex series of 16 varieties of a single species. Isely, who had been a strong proponent of splitting of Schrankia at both genus and species levels (Isely, 1971, 1973), later came to accept Barnebys conclusions in all regards (Isely, 1998). Nevertheless, the conservative species approach is accepted here with some reservations, and the complex is in need of more detailed taxonomic study.