Glabrescent, scrambling annual. Leaf trifoliolate. Petiole 1.5-13 cm long; leaflets 5-16 cm long, 1-12.5 cm broad, ovate-lanceolate; lateral leaflets oblique, acuminate to obtuse, mucronulate, glabrous or sparsely pubescent on both surfaces; petiolule 2-5 mm long; stipule submedifixed, 8-25 mm long. Inflorescence axillary, 2-12 flowered, peduncle 2-36 cm long; bract 3-5 mm long, bracteoles 3-5 mm long. Pedicel 1-4 mm long. Calyx glabrous, tube 3-5.5 mm long, teeth 2.5-14 mm long. Corolla white, greenish yellow or purple. Vexillum 1.2-3.3 cm long. Fruit up to 20 or 30 cm long, glabrous or minutely pilose. Seed 6-9 mm long.