15. Boehmeria japonica (Linnaeus f.) Miquel, Ann. Mus. Bot. Lugduno-Batavi. 3: 131. 1867.
野线麻 ye xian ma
Urtica japonica Linnaeus f., Suppl. Pl. 481. 1782; Boehmeria grandifolia Weddell; B. holosericea Blume; B. japonica var. appendiculata (Blume) Yahara; B. japonica var. longispica (Steudel) Yahara; B. longispica Steudel; B. pilushanensis Liu & Lu; B. platyphylla D. Don var. macrophylla Weddell; B. spicata var. duploserrata C. H. Wright; B. taiwaniana Nakai & Satake.
Subshrubs or herbs perennial, simple or few branched, 0.7-1.5 m tall; upper stems and branchlets densely appressed or patent strigose. Dioecious. Leaves opposite, subequal in size; stipules lanceolate, 0.8-1.2 mm; petiole 6-8 cm, appressed or patent strigose; leaf blade dark green or black when dry, suborbicular, orbicular-ovate, or ovate, 7-17(-26) × 5.5-13(-20) cm, papery, secondary veins 1-3 pairs along midvein, abaxial surface pubescent or sericeous along veins and veinlets, adaxial surface roughish, strigillose, base broadly cuneate, subrounded, or truncate, margin coarsely 7-14-dentate, teeth 6-20 mm, gradually larger distally, distal ones often biserrate, apex sometimes inconspicuously tricuspidate, lateral cusps shorter than terminal one. Glomerules on axillary unbranched, or sometimes few-branched, spikelike branches; male spikes 3-15 cm; female spikes 7-20(-30) cm. Male flowers 4-merous, sessile; perianth lobes elliptic, ca. 1 mm, strigose, connate at base. Fruiting perianth rhomboid-obovoid, compressed, ca. 1.8 mm, smooth, strigose on shoulder, base stipitate or cuneate, apex with short neck, 2-toothed. Fl. Jun-Aug, fr. Sep-Nov.
Forest margins, thickets, along streams in hills and mountains; 300-600 m in N and SE China, 1000-1300 m in SW China. Anhui, Fujian, Guangdong, Guangxi, Guizhou, S Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Taiwan, SE Yunnan, Zhejiang [Japan].
The fibers are used to make ropes and cloth. The leaves are used agriculturally as fodder and medicinally to relieve internal fever.
The earliest reference to this species is an excellent plate published by Houttuyn (Nat. Hist. 11: 291, pl. 72, f. 2. 1779), but that author did not ascribe any binomial to the plant in question. Boehmeria japonica and the following four species in this account, B. tricuspis, B. silvestrii, B. spicata and B. allophylla, make up a complex containing intermediate forms, because of which the status of the species remains uncertain.