Seed morphology: an addition to the taxonomy of Tephrosia (Leguminosae, Papilionoideae, Millettieae) from South America

Seed morphology was studied using scanning electron microscopy in 13 species, one subspecies and one forma of Tephrosia Pers. (Leguminosae, Papilionoideae, Millettieae) occurring in South America. Macromorphological and micromorphological characters were examined, including seed form, colour and size, testa pattern, reticulum anticlinal wall, boundaries of anticlinal wall and hilum form. Crested and simple-reticulate testa patterns were predominant. A foveolate pattern, multifoveolate pattern and subgrooved pattern are all recorded for the first time in this genus. The macromorphological characters displayed continuous variation in shape and size and are thus are not significant for species separation. The data obtained in this study together with data from the literature provide additional characters to help classify the genus. A key to the taxa under study is presented.