Description from Flora of China
Urtica stimulans Linnaeus f., Suppl. Pl. 418. 1782; Laportea annamica Gagnepain; L. hainanensis Merrill & Metcalf; L. stimulans (Linnaeus f.) Miquel.
Shrubs or small trees, straight, branches widely spreading. 3 m tall, bark whitish gray, lenticellate, leaf scars conspicuous, otherwise smooth; upper stem and branches glabrous, without stinging hairs, Stipules brownish, caducous, ovate, ca. 0.7 cm, leathery, margin herbaceous, puberulent abaxially; petiole 1.5-4 cm, with stinging hairs and dense punctiform cystoliths on both surfaces; leaf blade light green, obovate or oblong-lanceolate, 6-17 × 2-5 cm, papery or leathery, penniveined, lateral veins 6-8 each side, adaxial surface sparsely armed with short, stinging hairs, abaxial surface sparsely pubescent and armed with stinging hairs, base often cuneate, margin entire, sometimes inconspicuously serrulate at apex, apex acuminate, acumen often sharp; cystoliths minutely punctiform, conspicuous adaxially and along veins abaxially. Inflorescences in distal axils of branches, racemose, shorter than leaves; female inflorescences longer than leaves, long pedunculate, armed with stinging hairs. Male flowers sessile, in bud 1.5 mm; perianth lobes 4, elliptic, setulose; stamens 4; rudimentary ovary obpyramidal, 0.8 mm. Female flowers slightly sunken in a row on slightly fleshy flabellate peduncular receptacle, sessile, ca. 1 mm; perianth lobes 4, connate 1/2 of length, unequal, 2 lateral lobes wider, enclosing the ovary, triangular-ovate, ca. 0.4 mm, sparsely puberulent and armed with short stinging hairs; stigma somewhat straight, filiform, ca. 3 mm. Achene subglobose, oblique, compressed, ca. 3 mm in diam., inconspicuously verrucose; persistent perianth forming a minute cupule at base. Fr. Apr.
Forests; 100-600 m. Guangdong, Hainan, Taiwan [Indonesia, Laos, Malaysia, Philippines, Thailand, Vietnam; Borneo].