山葛薯 shan ge shu

Rhizome horizontal, irregularly branched, cylindric, to 5 cm thick; cork brown-black. Stem twining to left, glabrous, smooth. Leaves alternate, simple; petiole subequaling leaf blade; leaf blade drying blackish, ovate, narrower distally on stem, 7.5--20 × 4.5--11.5 cm, papery, glabrous, smooth, basal veins 7, reticulate veins raised, base cordate with acute sinus, margin entire or undulate, apex acuminate. Male spike solitary, rarely 2 or 3 together, lax, to 17 cm, often gathered into large, terminal panicles. Male flowers: in cymules of 2--6, rarely solitary, shortly pedicellate; perianth light yellow, lobes ovoid, ca. 2 mm, shorter than perianth tube; stamens 6, inserted at base of perianth, filaments reflexed. Female spikes to 20 cm; rachis very slender. Female flowers: staminodes 6, filiform. Capule reflexed, brown to dark brown, (1.5--)2--2.5 cm, base and apex truncate; wings 1--1.7 cm wide. Seeds inserted near middle of capsule, winged all round. Fl. Apr--Jul, fr. Aug--Oct.

Scrub forests, mountain slopes; 1200--1800 m. Guangxi, Yunnan [Vietnam].