Rhynchosia

A glabrous to somewhat pubescent, perennial, twining or sub-erect legume. Stems slender, numerous, 80 to 120 cm long. Stipules 2 to 3 mm long, lanceolate. Leaves trifoliate. Leaflets rhomboid, ovate or sub-orbicular to broad-acute, apex acute or rounded, 0.5 to 3 cm long x 0.5 to 3 cm wide, glabrescent to velvety. Inflorescence a lax 6- to 12-flowered raceme, 5 to 10 cm long. Calyx 3 to 4 mm long; five acuminate lobes. Corolla yellow, 1 cm long. Standard 5 to 7 mm long. Keel as long as the standard, wings shorter. Pods 1 to 1.5 cm long x 0.4 to 0.6 cm wide, black when ripe, two seeded, oblong, finely pubescent, slightly impressed between seeds, shortly beaked. Seeds monocoloured, black or brown, c. 3 mm long, with a short hilus.