Herbs or subshrubs, perennial, monoecious. Stems purplish when dry, straight, many branched, 100-200 cm tall; upper stem, branches, and petioles sparsely armed with stinging hairs; hairs 3-4 mm, thick. Stipules early caducous, triangular-ovate, ca. 3 mm, apex 2-cleft; petiole 4-8 cm; leaf blade usually purplish abaxially, dark green adaxially, broadly ovate or cordate, 5-12 × 4-10 cm, papery, lustrous, 3-veined, lateral basal pair reaching middle and anastomosing with adjacent lateral veins, lateral veins 3 each side of midvein, anastomosing before margin, abaxial surface sparsely armed with stinging hairs, adaxial surface appressed setulose and with long, stinging hairs, base often truncate, rarely shallowly cordate or abruptly attenuate, margin coarsely dentate, apex acuminate; cystoliths minutely punctiform, adaxially conspicuous. Male inflorescences in proximal axils, paniculate, to 8 cm; female inflorescences subterminal, to 20 cm, peduncle 7-10 cm. Male flowers subsessile, in bud ca. 1.5 mm; perianth lobes (4 or)5, elliptic, setulose, apex not corniculate; stamens 5; rudimentary ovary obpyramidal, 0.3 mm. Female flowers pedicellate; strongly laterally obovate-winged; perianth lobes 4, almost free, strongly unequal, dorsal lobe ovate, concave, ca. 0.3 mm, 2 lateral lobes largest, enclosing the ovary, narrowly ovate, ca. 0.7 mm, ventral lobe smallest, triangular-ovate, ca. 0.2 mm. Ovary stipitate, asymmetrically triangular-ovoid; stigma reflexed, filiform, 2-3 mm. Achene obovoid, strongly compressed, ca. 2 mm in diam., verrucose; stipe strongly reflexed, ca. 0.4 mm. Fl. Jun-Aug, fr. Aug-Nov.
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