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. Inflores-cences on old branches or axillary, 20-38 cm, with 5-10 nodes spaced throughout most of length; bracts ovate, ca. 2 mm, cadu-cous; bracteoles very early caducous; pedicels 1-1.5 cm, hairy. Calyx hairy; tube 1-1.5 × 1.5-2.5 cm; lateral lobes broadly tri-angular, 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, al-most 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.

● Dense or open woodlands, rocky areas, moist hillsides and val-leys; 800-2500 m. Fujian, Guangdong, Guangxi, Guizhou, Jiangxi, Si-chuan.
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.
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.