赤麻 chi ma

Boehmeria platanifolia Franchet & Savatier var. silvestrii Pampanini, Nuovo Giorn. Bot. Ital., n.s., 22: 278. 1915.

Herbs perennial or subshrubs, simple or few branched, 0.6-1 m tall; upper stems and branchlets sparsely strigillose. Dioecious or monoecious. Leaves opposite, unequal or subequal in size; stipules lanceolate, 5-7 mm; petiole 1.5-4(-8) cm, sparsely strigillose; middle leaf blade 5-angled or orbicular-ovate, 5-8(-13) × 4.8-7.5(-13) cm, thinly herbaceous, secondary veins 1-3 each side of midvein, both surfaces sparsely strigillose or abaxial surface sometimes glabrous, base broadly cuneate or subtruncate, apex often 3- or 5-cuspidate, sometimes caudate; upper leaf blade gradually smaller, base broadly cuneate or subrounded, margin 8-10-dentate, denticles gradually larger distally, apex caudate or inconspicuously tricuspidate. Glomerules on axillary, lax, unbranched spikelike flowering branches; male or bisexual ones in proximal axils; female ones in distal axils, 4-11(-20) cm. Male flowers 4-merous, subsessile; perianth lobes boat-shaped to elliptic, ca. 1.5 mm, sparsely strigillose, connate to middle; rudimentary ovule ellipsoid, ca. 0.8 mm. Fruiting perianth rhomboid-obovoid, compressed, ca. 1.5 mm, smooth, strigillose on shoulder, base cuneate or stipitate, apex with short neck, 2-toothed. Fl. Jun-Aug, fr. Sep-Nov.

Forest margins, thickets, along streams in hills and mountains; 100-1400 m in C and N China, 2100-2600 m in SW China. N and W Hebei, W Henan, W Hubei, S Gansu, SE Jilin, S Liaoning, S Shaanxi, E Shandong, Sichuan [Japan, Korea].

The fibers are used to make ropes and cloth.