10. Urtica thunbergiana Siebold & Zuccarini, Abh. Math.-Phys. Cl. Königl. Bayer. Akad. Wiss. 4(3): 214. 1846.
咬人荨麻 yao ren qian ma
Urtica macrorrhiza Handel-Mazzetti.
Herbs perennial, dioecious or monoecious. Rhizomes woody. Stems caespitose, simple or many branched, 60-150 cm tall, ca. 1 cm in diam., antrorsely setulose, armed with spreading stinging hairs, dense in lower parts, sparser in upper parts. Stipules brownish or greenish, interpetiolar, connate, narrowly ovate, oblong or oblong-ovate, 7-15 mm, herbaceous, with several ribs, puberulent, with cystoliths, apex shallowly 2-cleft or emarginate, petiole 1-9 cm, armed with stinging and retrorsely setulose hairs; leaf blade greenish brown abaxially, dark brownish adaxially when dry, triangular-ovate, oblong-ovate, broadly ovate or cordate, 5-12 × 2.5-11 cm, herbaceous or thinly papery, 5-veined, lateral basal veins arcuate, reaching distal margin, secondary veins 2 or 3 each side, both surfaces sparsely armed with stinging and appressed setulose hairs, base truncate to cordate, margin coarsely doubly dentate or incised-lobed, lobes 1- or 2-denticulate each side, apex shortly acuminate or acute; cystoliths botuliform on both surfaces. Inflorescences unisexual, male inflorescences in proximal axils; paniculate, with a few branches, longer than petioles; female ones in distal axils. Male flowers subsessile, in bud 1-1.2 mm; perianth lobes connate 1/2 of length, sparsely puberulent. Female perianth lobes connate at base, dorsal-ventral lobes brownish, elliptic-ovate, setulose, lateral lobes broadly ovate, 1/4-1/3 as long as dorsal ones. Achene light brownish, broadly ovoid, slightly compressed, ca. 1 mm, conspicuously verrucose, invested by persistent perianth lobes. Fl. Jul-Sep, fr. Aug-Oct.
Shady, moist places in forests, along streams, valleys; 1200-2500 m. Taiwan, W Yunnan [S Japan].
The coarsely doubly dentate margins of the leaves on the main stem of the type of Urtica macrorrhiza, from Yunnan, correspond very well with U. thunbergiana, from Taiwan and, outside China, Japan. This disjunction in distribution is most unusual.