Dioscorea biformifolia S. J. Pei & C. T. Ting

Rhizome horizontal, irregularly branched, cylindric; cork purplish black, rough. Stem twining to left, glabrous, smooth but inconspicuously shortly prickly near nodes. Leaves alternate, simple or sometimes 3-foliolate distally on stem; leaf blade of simple leaves drying dark grayish brown, lanceolate, 12--17 × 7--8 cm, slightly leathery, glabrous, basal veins 3, rarely to 9 (when outermost ones much shorter), base deeply cordate with narrow sinus and basal lobes sometimes overlapping, margin entire or slightly undulate, apex acuminate; middle lobe or leaflet lanceolate, 10--20 × 1.5--3 cm, lateral lobes or leaflets much smaller, oblique, rounded, or acuminate. Male spike to 9 cm, solitary along specialized, lateral shoots or in axillary panicles to more than 20 cm. Male flowers: solitary or in dense clusters of 2--4, sessile; bracts rounded; perianth yellowish green, saucer-shaped, lobes ovate, ca. 1.5 × 1 mm, apex obtuse; stamens 6, inserted at base of perianth, filaments short. Female spike lax. Capsule reflexed, light brown, obovoid, ca. 1.5 cm, base rounded, apex truncate; wings ca. 0.8 cm wide. Seeds inserted near middle of capsule, winged all round. Fl. Apr--Jul, fr. Jul--Oct.

Yunnan.

* Scrub forests, forest margins, mountain slopes; 600--1800 m.