Rhynchosia is a large and diverse genus in the subfamily Faboideae, tribe Phaseoleae, subtribe Cajaninae of the Leguminosae. It consists of nearly 200 species and is distributed in warm temperate and tropical regions of both eastern and western hemispheres. They occur as herbs, sub-shrubs or vines, and the horticultural potential of some twining species with numerous large, showy flowers or attractive foliage has been largely neglected.. This treatment, restricted primarily to the species indigenous to the western hemisphere, recognizes 59 taxa, comprising 51 species and 8 varieties. Includes keys, descriptions, distribution maps, and black and white illustrations.