A Taxonomic Study of the Genus Amphicarpaea (Leguminosae)

Abstract

The genus is composed of 3 species each of which is confined to a separate continent: A. africana (in Africa); A. edgeworthii (in Asia); and A. bracteata (in North America). The latter, widespread species is treated as a poly- morphic group without infraspecific categories. Amphicarpaea with a basic chromo- some number of x = 10 is most closely related to the genus Cologania (x = 11). A descriptive account of the species is given along with complete synonymy and additional comments of a systematic nature. No new names or taxa are published. The genus Amphicarpaea, as treated in the present paper, is com- posed of 3 species of herbaceous, twining vines, each of which is con- fined to a separate continent (Fig. 1): A. africana (in Africa); A. edgeworthii (in Asia); and A. bracteata (in North America). Elliott established the genus in typifying it with Glycine monoica L., which Fernald (1933) later showed to be a synonym of the earlier Linnaean species, Glycine bracteata. After Elliott most workers have recognized the genus as valid. Only two good species were added, viz. A. edgeworthii in 1852 and A. africana in 1921. Numerous other names have been proposed for the variable elements of A. bracteata; 14 names, based on as many types, were proposed for this species by several workers (8 of these were proposed by Rafinesque).