9. Urtica dioica Linnaeus, Sp. Pl. 2: 984. 1753.
异株荨麻 yi zhu qian ma
Herbs perennial, dioecious, rarely monoecious. Rhizomes woody, stoloniferous. Stems simple or few branched, 40-100 cm tall; stems and petioles often densely or sometimes sparsely covered with stinging and setulose hairs. Stipules free, linear, (2-)5-8 mm; petiole 2.5-4 cm; leaf blade ovate, sometimes lanceolate, 5-13 × 2.5-6 cm, often herbaceous, (3-)5-veined, lateral basal veins reaching distal margin and anastomosing, secondary veins 3-5 each side, adaxial surface sparsely covered with stinging and setulose hairs, abaxial surface often densely covered with long, stinging and setulose hairs along veins, base cordate, margin coarsely 15-21-serrate or -dentate, teeth often incurved-tipped, apex acuminate or long acuminate; cystoliths punctiform. Inflorescences paniculate, 3-7 cm; female inflorescences with slender axes, often drooping in fruit. Male flowers in bud ca. 1.4 mm; perianth lobes connate 1/2 of length, puberulent. Female flowers: perianth lobes connate at 1/4 of lower part, dorsal-ventral lobes elliptic-ovate, 1.2-1.5 mm, sparingly setulose, lateral lobes narrowly elliptic, 2-3 × as long as the dorsal ones, Achene brownish gray, ovoid or narrowly ovoid, slightly compressed, 1-1.2(-1.4) mm, smooth, invested by persistent perianth lobes. Fl. Jun-Aug, fr. Aug-Sep.
Moist places in forests, thickets, grasslands, stream banks; (500-) 2200-5000 m. E Gansu, Qinghai, NW Sichuan, W Xinjiang, Xizang [Afghanistan, C Himalayas; N Africa, Europe, North America].
Dmitry Geltman (pers. comm.) notes that U. dioica subsp. sondenii (Simmons) A. Löve & D. Löve (U. dioica var. sondenii Simmons; U. sondenii (Simmons) Avrorin ex Geltman) occurs in the mountainous regions of Xinjiang (Altay Shan, etc.).