双花秋海棠 shuang hua qiu hai tang

Herbs, rhizomatous. Rhizomes 3-10 mm in diam.; internodes 3-6 mm. Leaves all basal; stipules generally persistent, ovate-triangular, 4-10 × 3-6 mm, abaxially subglabrous; petiole 4-22 cm, hirsute-villous; blade adaxially without white bands or patches, obliquely broadly ovate, 8-25 × 7-23 cm, papery, abaxially pubescent, more densely so on veins, adaxially sparsely setulose or hispidulous, basally 5-7-veined, tertiary veins percurrent and reticulate, base deeply cordate, margin crenulate and irregularly denticulate, apex obtuse, sometimes rounded or acute. Inflorescences 4-13-flowered; peduncle 5-7.5 cm, glabrous or sparsely pilose; bracts caducous, oblong or ovate to broadly lanceolate, 2-3 × 1.2-2.5 mm. Staminate flowers: pedicel 8-15 mm; tepals 4, outer 2 pinkish or slightly yellowish green, broadly ovate or suborbicular, 4-11 × 5-9 mm, abaxially glabrous or sparsely pilose, inner 2 obovate or elliptic, 6-9 × 3-5 mm, glabrous; stamens 24-30; filaments fused into a short column at base, anthers obovoid, 0.6-0.9 × 0.5-0.75 mm. Pistillate flowers: pedicel 7-14 mm; tepals 3, outer 2 suborbicular, 6-9.5 × 6-8 mm; ovary glabrous or pilose, 1-loculed with parietal placentation; styles 3, free. Capsule nodding, 6-9 mm, glabrous or pilose, unequally or subequally 3-winged; abaxial wing lunate, 2-4.5 mm; lateral wings smaller. Fl. Jan-May, fr. Feb-Jul.

● Limestone rocks or on rocky walls, in moist rocky caves; 200-400 m. Yunnan (Malipo).

Begonia biflora is similar to B. bonii Gagnepain, which is endemic to Vietnam, but the former species differs in having a much shorter peduncle and the stipules are not hirsute abaxially.