Climbers, erect shrubs, or small trees, to 10 m tall. Branches glabrous, with scattered recurved prickles. Leaves with tomentose rachis 30-40 cm; stipules absent; pinnae 7-20 pairs, 5-16 cm, with prickles in pairs at base; leaflets 12-30 pairs, sessile, linear, ca. 15 × 5 mm, membranous, lateral veins conspicuous, 4-6 pairs, base obliquely truncate, apex obtuse-rounded. Racemes or panicles terminal or axillary, 20-60 cm, pubescent. Pedicels 8-20 mm, not jointed above base. Sepals 5, unequal, lowest one deeply cucullate, ca. 10 × 7 mm, other 4 ca. 6 × 4 mm, usually ciliate. Petals yellowish, often tinged with spots. Stamens 10; filaments 1-1.4 cm, hairy at lower part. Pis­til 1-1.6 cm; ovary sessile, pubescent or glabrous, 4- or 5-ovuled; style inclined; stigma truncate, ciliate. Legume blackish when dry, indehiscent, often twisted, 3.5-9 × 2-3.5 cm, base rounded, apex obtuse, shortly beaked, both sutures thickened, often constricted between seeds, exocarp and endocarp adnate, swollen on seeds, transversely cleft when ripe. Seeds 1-5(-7), subglobose, ca. 1 cm in diam. Fl. Jun-Aug, fr. Jul-Aug.

Among bushes on mountain slopes; ca. 1400 m. Guangdong (Guangzhou, cultivated), Yunnan [India, Indonesia, Malaysia, Myan­mar].