Urtica interrupta Linnaeus, Sp. Pl. 2: 985. 1753; Fleurya interrupta (Linnaeus) Gaudichaud-Beaupré.

Herbs annual, monoecious. Stems straight, branched, 40-100 cm tall; upper stems and petioles sparsely armed with short stinging and pubescent hairs. Stipules ovate-oblong, ca. 4 mm, setulose along rib abaxially, apex 2-cleft 1/2 of length; petiole 3-9 cm; leaf blade ovate or cordate, 5-8 × 4-5.5 cm, herba-ceous, 3-veined, lateral basal pair reaching middle margin, lateral veins 5 or 6 each side of midvein, reaching teeth, both surfaces sparsely armed with short, stinging hairs, base abruptly cuneate or shallowly cordate, margin serrate, apex acuminate; cystoliths botuliform, regularly arranged abaxially along veins. Inflorescences axillary, long spicate, to 25 cm, glomerules at intervals along elongated peduncle consequent upon great reduction of the lateral branches, sparsely armed with minutely stinging hairs. Male flowers pedicellate, in bud ca. 1.2 mm; perianth lobes (3 or)4, connate 1/2 of length, obovate, puberulent, apex corniculate; stamens (3 or)4; rudimentary ovary obpyramidal, 0.5 mm. Female flowers: pedicel to 1.5 mm, not winged; perianth lobes 4, free, unequal, dorsal lobe ovate, concave, ca. 0.4 mm, 2 lateral lobes largest, enclosing the ovary, broadly ovate, ca. 0.4 mm, ventral lobe smallest, triangular ovate, ca. 0.3 mm. Ovary asymmetrically triangular; stigma reflexed, filiform, 3-fid, ca. 0.3 mm. Achene obliquely triangular, compressed, ca. 1.3 mm in diam., with triangular ridge enclosing a warty depression, persistent lateral perianth lobes forming a small basal cup. Fl. Jul-Aug, fr. Aug-Sep.

Disturbed, moist places of dense forests, streams; 600-1000 m. Taiwan, SW Yunnan [India, Indonesia, Japan, Malaysia, Myanmar, Philippines, Sri Lanka, Thailand, Vietnam; Africa].