Botany of Sesbania
The genus Sesbania is divided into at least four subgenera, of which two, Sesbania and Agati, contain species of potential agricultural value. The subgenus Sesbania comprises most of the species, is distributed world wide, and contains species known as green manures and as forages, such as S. bispinosa and S. sesban. The genus Sesbania Scopoli, consisting of about 50 species, pantropically distributed, is placed in the family Leguminosae, subfamily Papilionoideae. Some Sesbania species are relatively short-lived perennials; the majority are annuals. Taxonomic studies are generally vague in describing growth duration. Known perennials include S. grandiflora, which may live for twenty years or more, S. formosa, S. sesban, and the Hawaiian species. The Sesbania germplasm resource base has received inadequate attention. Seed scarification is recommended when sowing sesbanias in order to obtain uniform, complete, and rapid germination.