127. Begonia pulvinifera C. I Peng & Yan Liu, Bot. Stud. 47: 319. 2006.
肿柄秋海棠 zhong bing qiu hai tang
Herbs. Rhizomes elongate, creeping, to 2 cm in diam. Leaves arising from rhizome; stipules triangular, 2.8-3 × 1.7-1.9 cm, glabrous, margin entire, apex acuminate or cuspidate, persistent; petiole greenish, to 24 cm, glabrous, base reddish brown, swollen; blade green, peltate, ovate, slightly asymmetric, 14-21 × 8-14 cm, glabrous, venation palmate, base rounded, margin entire or nearly so, apex acuminate, shortly caudate. Inflorescences 17-45 cm, glabrous; peduncle 34-37 cm; bracts reddish brown, narrowly ovate, 2-2.5 × 0.9-1.2 cm, glabrous, margin entire, apex acute to acuminate. Tepals pinkish, glabrous. Staminate flowers: pedicel 2.2-3.5(-4.8) cm; tepals 4, glabrous, outer 2 broadly ovate, 2.3-2.8 × 2.2-2.5 cm, inner 2 oblanceolate, 16-18 × 5-8 mm, apex obtuse; stamens more than 100; filaments nearly free, 3-5 mm; anthers obovoid, ca. 1 mm, apex truncate or subemarginate. Pistillate flowers: pedicel 1.3-1.5 cm; tepals 3, glabrous, outer 2 depressed-ovate, 1.8-2 × 2.4-2.6 cm, inner 1 oblanceolate, 1.2-1.4 × 4-5 mm; ovary glabrous, unequally 3-winged, 3-loculed; placentae axile, bilamellate; styles 3, 4-4.5 mm, fused at base; stigmas 2-cleft, in a spiraled band. Infructescences 17-45 cm; capsules nodding, ca. 3.1 cm, unequally 3-winged; abaxial wing lunate, ca. 5 mm; lateral wings smaller, 2-3.5 mm.
● Forests, on limestone rocks; ca. 300 m. Guangxi (Jingxi).
This species is known only from the type gathering. It resembles Begonia cavaleriei but is distinguishable by having stipules triangular with the apex acuminate or cuspidate, the petiole pulvinate, and bracts ovate with the apex acute or acuminate. It is also similar to B. wangii but differs by having the petiole with a reddish brown swollen base, the abaxial surface of the leaf blade pale green, tepals obtuse, those of staminate flowers 4, those of pistillate flowers 3, and the ovary with axile placentation throughout.