Tubers cylindric; transverse section white. Stem twining to left, sparsely pubescent or glabrous. Leaves alternate, simple; petiole 2--5.5 cm; leaf blade abaxially often drying pale gray, triangular-ovate to narrowly ovate, 6--13 × 3--10 cm, adaxially glabrous, abaxially sparsely pubescent, basal veins 7 or 9, base shallowly cordate with broad sinus, apex caudate-acuminate. Male thyrses solitary or 2--4 together, to 18 cm, pubescent. Male flowers: usually in cymules of 2--4; bracts ovate or lanceolate-ovate, apex acuminate; perianth sparsely brown dotted, abaxially sparsely pubescent, lobes lanceolate, ca. 1.5 mm; stamens 6, filaments longer than anthers, anthers dorsifixed, introrse. Female spikes 8--18 cm, sparsely pubescent. Female flowers: bracts ovate-lanceolate; perianth lobes narrowly ovate, ca. 1.5 mm, apex subacute; stigma 3-fid, reflexed. Capsule reflexed, oblong-obovoid or narrowly obovoid, ca. 2 cm, glabrescent, base cordate or rounded, apex emarginate; wings 0.5--0.8 cm wide, sometimes slightly undulate. Seeds inserted near base of capsule; wing pointing toward capsule apex. Fl. Jul--Sep, fr. Oct--Jan.

* Forests; 1100--2600 m. Yunnan.