Stems firm, slender, glabrous, wide-twining, climbing to a length of 60 or 70 ft. Stipules small, lanceolate, deciduous. Petioles 4–5 in. long, firm, slender, glabrous; leaflets subcoriaceous, the central one ovate-oblong, 3–6 in. long, 2–3 in. broad, cuspidate or acuminate, the base rounded; petiolule 1 1/2 in. long; the lateral ones larger and very unequal-sided, both sides glabrous. Flowers in lax racemes on a firm zigzag rachis on firm slender glabrous elongated peduncles sometimes 6 or 7 ft. long. Bracteoles cymbiform, grey-silky, an inch or more long, deciduous. Pedicels 4–5 lines long, cernuous. Calyx broad-campanulate, 1/2– 5/8 in. deep, adpressed grey-silvery and scattered over with deciduous yellow bristles, the upper lip rounded entire, the lower with three short deltoid teeth. Corolla pale yellow, protruding an inch beyond the calyx. Pod oblong, 4–5 in. long, 1 1/2 in. thick, coriaceous, lamellated and bristly as in the preceding, 2–3-seeded.
