Prostrate or rarely twining herb; stems wiry, to 2 m long or more, hirsute at first, glabrescent later. Leaflets orbicular to broad-obovate, 6–35 mm long, 6–35 mm wide, upper surface more or less glabrous, lower surface pubescent, apices often notched, sometimes mucronate; petiole 0.5–5 cm long; lateral leaflets subsessile; upper leaflet on petiolule 2–9 mm long; stipules cordate, c. 5 mm long, leafy; stipellae filiform, c. 2 mm long. Flowers usually 1 or 2; peduncle 5–30 mm long; pedicel 5–25 mm long; bracts 2–5 mm long, pubescent, persistent; calyx 6–8 mm long, pubescent; corolla 15–25 mm long, scarlet, rarely white; standard obovate with a yellow basal callus; wings shortest; keel nearly as long as standard. Pod more or less cylindric, 20–50 mm long, 5–8 mm wide, pubescent; seeds 5–8, ovoid, 3–4 mm long. Flowers mostly Aug.–Nov.