3. Urtica urens Linnaeus, Sp. Pl. 1: 984. 1753.
欧荨麻 ou qian ma
Herbs annual. Stems branched, 10-60 cm tall, sparsely puberulent and somewhat densely armed with stinging hairs; lower internodes 4-7 cm, upper internodes 1-3 cm. Stipules free, narrowly triangular, 1-2.5 mm, ciliate; petiole 1-2.5 cm, puberulent, sparsely armed with stinging hairs; leaf blade broadly elliptic, sometimes ovate or obovate, 1.2-6 × 0.6-3 cm, 5-veined, often subglabrous except for sparse stinging hairs on both surfaces, base broadly cuneate or rounded, margin 6-11-dentate, apex obtuse-rounded; cystoliths punctiform, distinct adaxially. Inflorescences containing proximal female flowers and distal male flowers, spicate, 0.5-2.5 cm. Male flowers short pedicellate, in bud ca. 1.2 mm; perianth lobes connate 1/2 of length, puberulent. Female flowers: perianth lobes connate at base, dorsal-ventral lobes ovate, equaling achene, often with 1 stinging hair on dorsal rib, sparsely setulose along margin, lateral lobes ovate, ca. 5 times as small as others. Achene brownish gray, ovoid, compressed, 0.8 mm, verrucose, invested by persistent perianth lobes. Fl. May-Jul, fr. Aug-Sep.
Forest margins, roadsides, near villages; 500-1000 m in N China, 2800-2900 m in SW China. Liaoning, Qinghai, Xinjiang (Altay region), S Xizang [Africa, Asia, Europe, very widely distributed in temperate regions and tropical highlands].
Wright (in 1899) and Handel-Mazzetti (in 1929) reported this species from Zhejiang, in SE China; however, we have seen no material from there. If present in Zhejiang, the plants must be naturalized.