Large woody vines. Young stems glabrous or with fine stiff adpressed pale hairs at nodes. Leaves 17-30 cm; petiole 8-20 cm, with sparse stiff spreading hairs; stipels not persistent; leaflets almost leathery, glabrous or sparsely hairy abaxially, often glossy adaxially, lateral veins 3-5 pairs, gently curved; terminal leaflet ovate, elliptic, or slightly obovate, usually long and narrow, 9-16 × 2-6 cm, base rounded or slightly cuneate, apex with ± distinct acumen 1.3-2.2 cm; lateral leaflets 9-16 cm, width ratio of abaxial to adaxial halves 1.7-2:1. Inflores­cences on old branches or axillary, 20-38 cm, with 5-10 nodes spaced throughout most of length; bracts ovate, ca. 2 mm, cadu­cous; bracteoles very early caducous; pedicels 1-1.5 cm, hairy. Calyx hairy; tube 1-1.5 × 1.5-2.5 cm; lateral lobes broadly tri­angular, 5-8 mm, lowest narrowly triangular, 5-15 mm, upper lip usually equal to lateral lobes. Corolla white or greenish white; standard 3.5-4.5 cm, apex with margin conspicuously brown pubescent in apical 1/3-1/2; wings 6.2-7.1 cm, margin pubescent like standard around apex; keel 7.5-8.7 cm. Legume linear but markedly constricted between seeds, 30-45 × 3.5-4.5 cm, 1-1.5 cm thick, woody, densely pubescent, young legume clothed with dense short fine spreading velvety dark or red-brown pubescence and reddish brown caducous bristles, both margins with pair of narrow woody wings 3-5 mm wide, woody septum between seeds ca. 4 mm thick. Seeds 5-13, black, al­most reniform, to ca. 2.8 × 2 cm, 8-10 mm thick, usually glossy; hilum length 1/2-3/4 of seed perimeter. Fl. Apr-Jun, fr. Jun-Nov.

Mucuna birdwoodiana is distinctive in its narrow leathery glossy often glabrous leaves without persistent stipels; large white, often drying pale green, flowers with conspicuously pubescent margins at their apex; and large woody narrowly linear velvety pubescent legume with narrow marginal wings. It is not easily confused with any other species.

This species is used medicinally and as a starch.

● Dense or open woodlands, rocky areas, moist hillsides and val­leys; 800-2500 m. Fujian, Guangdong, Guangxi, Guizhou, Jiangxi, Si­chuan.