Description from Flora of China
Dioscorea glabra var. longifolia Prain & Burkill; D. hongkongense Uline ex R. Knuth; D. nummularia Roxburgh (1832), not Lamarck (1789).
Tubers cylindric, developed from short, thick rhizome; cork deciduous; transverse section white, drying light yellow. Stem twining to right, glabrous, prickly at base. Leaves alternate basally on stem, opposite distally on stem, simple; leaf blade drying blackish, usually ovate or long elliptic-ovate to lanceolate, 5--17(--24) × 0.5--10(--13) cm, glabrous, basal veins 5--9, base cordate to truncate or rounded, rarely sagittate or hastate, apex acuminate or caudate. Male spikes solitary or 2--4 together, 1--2.5 cm, usually in narrow, axillary panicles to 14 cm; rachis straight. Male flowers: outer perianth lobes orbicular, ca. 1 mm, inner ones obovate, smaller but thicker than outer; stamens 6, inflexed. Female spikes solitary or paired, to 25 cm. Capsule not reflexed, oblate, 1.5--2.5 cm; wings 1.2--2.2 cm wide. Seeds inserted near middle of capsule, winged all round. Fl. Sep--Dec, fr. Dec--Jan.
Evergreen broad-leaved forests, scrub forests, mountain slopes, valley sides, roadsides; 200--1500 m. W Guangxi, S Yunnan [Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Thailand, Vietnam].