Annual, climber or suberect, stem pubescent to glabrescent. Leaf trifoliolate, petiole 4-9 cm long, leaflets 4.5-15 cm long, 2.5-6.5 cm broad, ovate to ovate-rhombic, acuminate, lateral leaflets oblique; petiolule 1.5-2.5 mm long; stipules 4 mm long. Inflorescence 1-3-flowered, peduncle 0-5 cm long. Bracts 3 mm long; bracteoles 5-6 mm long. Pedicel 3-10 mm long. Calyx pubescent, tube 2-3 mm long, teeth 1 mm long, upper 2 joined to form an emarginate lip. Corolla white, yellowish purple or pale-pink. Vexillum 1-1.9 cm long, glabrous. Keel 2.2 cm long, spirally incurved. Fruit 10-15 cm long, 1-1.3 cm broad, linear, lanceolate, pubescent or glabrous, 5-12-seeded.