Herbs, perennial, or subshrubs, stoloniferous, glabrous, dioecious, rarely monoecious. Stems gray green, erect, ascending, or scandent, often branched, longitudinally several angled when dry, to 2.5 m tall, woody at base, densely covered with cystoliths. Stipules deciduous, oblong, 1.5-2 mm, herbaceous; petiole unequal in length, 4-10 cm; leaf blade elliptic, ovate, or elliptic-ovate, unequal in size, 9-17 × 4.5-10 cm, membranous, 3-veined, lateral veins many, subtransverse, reticulate, cystoliths conspicuous adaxially, base rounded or broadly cuneate, margin coarsely crenate-serrate, apex caudate-acuminate, acumen serrulate. Inflorescences solitary; male inflorescence a globose capitate raceme, ca. 0.5 cm in diam., shorter than petiole; female ones cymose-paniculate, much shorter, 1-2 cm. Male flowers sessile, in bud ca. 1 mm; perianth lobes 4; stamens 4; rudimentary ovary small, subulate. Female flowers subsessile, in bud ca. 0.6 mm; perianth lobes connate at base, unequal, abaxial lobe cymbiform, longer, subapically corniculate; staminodes 3, inconspicuous, scale-like, oblong. Achene brownish, ovoid, ca. 1 mm, compressed, with 2 or 3 concentric rings of minute tubercles Fl. Aug-Sep, fr. Oct-Nov.

This species is here newly recorded for China.

4Warm wide-leaved forests, shaded wet places by streams, near streams; 1200-1800 m. NW Yunnan [Bhutan, NE India, Nepal, Sikkim].