89. Begonia longifolia Blume, Catalogus. 102. 1823.
粗喙秋海棠 cu hui qiu hai tang
Begonia aptera Hayata (1911), not Blume (1827), nor Roxburgh (1832), nor Decaisne (1834); B. crassirostris Irmscher; B. hayatae Gagnepain.
Herbs, erect. Rhizomes short, stout. Stems 0.5-1.5 m tall, well branched. Leaves cauline; stipules caducous, narrowly to broadly ovate, to 2.4 × 1.9 cm, glabrous, apex acuminate; petiole 8-15 cm, glabrous or subglabrous; blade lanceolate to broadly lanceolate, asymmetric, 8.5-29 × 3.4-11 cm, glabrous or subglabrous, venation palmate-pinnate, 7-10-veined, base oblique, cordate, margin remotely and irregularly denticulate. Inflorescences strongly reduced, to 5 cm, pendulous; bracts caducous, ovate to narrowly triangular, to 1.9 × 1.2 cm, thickly papery, glabrous, margin entire, apex mucronate to acuminate. Staminate flowers: pedicel 5-12 mm; tepals 4, white, outer 2 oblong to very broadly ovate, 0.9-1.3 cm × 5-10 mm, glabrous, inner 2 elliptic, 0.6-1.5 cm × 4-8.2 mm; stamens 49-93; filaments free, 0.7-2.5 mm; anthers lorate to broadly lorate, 1.7-2.6 mm, apex emarginate. Pistillate flowers: pedicel 5-12 mm; tepals 6, white, subequal, broadly elliptic to orbicular, 7-12 × 5-9 mm; ovary glabrous, 3-loculed; placentae axile, bilamellate; styles 3, fused at base; stigmas 2-cleft, spiraled. Capsule pendulous, subglobose, 1.1-1.8 cm in diam., wingless or 3-horned. Fl. Apr-May, fr. Jul. 2n = 22*.
Forests, shaded moist environments; 200-2200 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangxi, Taiwan, Yunnan [Bhutan, NE India, Indonesia, Laos, Malaysia, Myanmar, Thailand, Vietnam].
Nearly all species of Begonia are very narrowly distributed. Begonia longifolia is probably the most widespread species in the genus. It resembles B. acetosella when sterile, differing by being monoecious, having a 3-loculed ovary, 6-tepaled pistillate flowers, and a remotely denticulate leaf margin.