Description from Flora of China
Girardinia cuspidata Weddell in Candolle, Prodr. 16(1): 103. 1869; Laportea forrestii Diels; L. giraldiana E. Pritzel ex Diels; L. grossedentata C. H. Wright; L. macrostachya (Maximowicz) Ohwi; Sceptrocnide macrostachya Maximowicz.
Herbs, roots often fusiform, tuberous, 5-10(-30) × 0.3-0.5(-1) cm. monoecious. Stems often caespitose, slightly woody at base, 40-150 cm tall, upper stem sometimes purplish, often zigzagged, 5-angled, rarely branched; sterile axils with 1-3 woody bulbils, 3-5 mm in diam.; upper stems and petioles sparsely pubescent and sparsely armed with stinging hairs particularly at nodes and basally, glabrescent. Stipules early caducous, ovate-triangular, 3-4 mm, apex 2-cleft; petiole 3-14 cm; leaf blade ovate, elliptic or suborbicular, 7-22 × 3.5-17 cm, membranous or papery, 3-veined, rarely tripliveined, lateral basal pair reaching to middle margin, lateral veins 2-4 each side of midvein, both surfaces sparsely pubescent and sparsely armed with stinging hairs, sometimes glabrescent, base cordate, rounded, rarely subtruncate, margin grossly dentate, teeth increasing in size toward apex, sometimes doubly serrate, apex long caudate, cauda occasionally serrate; cystoliths minutely punctiform, adaxially conspicuous. Male inflorescences in proximal axils, paniculate, 8-17 cm; female inflorescences subterminal, long spicate, 15-25 cm, peduncle 2-8 cm, often with glomerules at intervals along usually unbranched peduncle, sparsely pubescent and armed with stinging hairs. Male flowers pedicellate or subsessile, in bud ca. 1.5 mm; perianth lobes 5, narrowly ovate, puberulent, apex not corniculate; stamens 5; rudimentary ovary obconic, 0.4 mm. Female flowers: pedicels ca.1.5 mm, not winged; perianth lobes 4, almost free, strongly unequal, dorsal lobe broadly ovate, concave, ca. 0.6 mm, 2 lateral lobes largest, enclosing the ovary, oblong-ovate, ca. 0.7 mm, setulose beneath, ventral lobe smallest, ovate, ca. 0.4 mm. Ovary short stipitate, enlarged in fruit, asymmetrically ovoid; stigma reflexed, filiform, ca. 2 mm. Achene obovoid, slightly compressed, ca. 2 mm, smooth; stipe 1-2 mm; persistent lateral perianth lobes slightly enlarged, ca. 1.5-1.8 mm. Fl. Jun-Jul, fr. Aug-Sep.
Forest margins, thickets, partly shady, moist places, roadsides; 800-2700 m. Anhui, SE Gansu, N Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangxi, S Shaanxi, Sichuan, SE Xizang [Japan, Myanmar].