火焰桑叶麻 huo yan sang ye ma

Urtica aestuans Linnaeus, Sp. Pl., ed. 2, 2: 1397. 1763; Fleurya aestuans (Linnaeus) Miquel; F. glandulosa Weddell.

Herbs annual, monoecious. Stems erect, few-branched, to 1.3 m tall; upper stems and petioles densely armed with stinging hairs and long gland-tipped hairs. Stipules ca. 10 mm, apex 2-cleft; petiole 7-11 cm; leaf blade broadly ovate, 8-17 × 6-13 cm, thinly papery, 3-veined, lateral basal pair reaching middle margin, lateral veins 3 or 4 each side of midvein, both surfaces armed with stinging hairs, denser on abaxial surface, base rounded or cordate, margin dentate, apex acuminate; cystoliths punctiform, adaxially conspicuous. Inflorescences axillary, often bisexual, rarely all male, paniculate, male inflorescences in proximal axils, shorter, bisexual inflorescences in distal axils, 10-20 cm, peduncle 7-14 cm, with stinging hairs and often long gland-tipped hairs. Male flowers pedicellate, in bud ca. 1.5 mm; perianth lobes 4 or 5, connate at base, cymbiform, with a few long gland-tipped hairs and sparsely setulose, apex corniculate; stamens 4 or 5. Female flowers: pedicel ca. 2 mm, not winged; perianth lobes 4, free, unequal, dorsal lobe ovate, ca. 0.25 mm, 2 lateral lobes largest, enclosing the ovary, broadly ovate, ca. 0.5 mm, ventral lobe minute. Ovary asymmetrically ovoid; stigma slightly reflexed, ligulate, ca. 0.3 mm. Achene obliquely ovoid, compressed, ca. 1.5 mm in diam., both central surfaces with inconspicuously warty depression; persistent lateral perianth lobes forming a small, basal cup. Fl. Aug-Sep, fr. Oct-Nov.

Disturbed moist places by streams in forests; 200-500 m. C Taiwan [pantropical weed found throughout tropical Asia from India to Indonesia, tropical Africa, Madagascar, tropical America, West Indies].