146. Begonia silletensis (A. Candolle) C. B. Clarke subsp. mengyangensis Tebbitt & K. Y. Guan, Novon. 12: 134. 2002.
厚壁秋海棠 hou bi qiu hai tang
Herbs, dioecious. Rhizomes elongate, to 3.6 cm in diam. Leaves basal; stipules caducous, 1.7-2.7 × 1-1.8 cm, membranous; petiole to 75 cm, densely minutely hairy; blade ovate or broadly ovate, asymmetric, (11-)13-53 × 11-40 cm, abaxially minutely hairy, adaxially subglabrous, venation palmate, 7-9-veined, base oblique, deeply cordate, margin remotely serrulate, apex caudate-acuminate. Inflorescences axillary and terminal, 1.2-6(-12) cm, minutely hairy; bracts caducous, membranous. Flowers fragrant. Staminate flowers: pedicel to 4.2 cm; tepals 4, white, broadly ovate, 2-2.6 × 1.7-2.2 cm, abaxially minutely hairy, inner 2 oblate-orbicular, 0.9-2.2 × 0.7-1.4 cm; stamens 115-122; filaments 1-2.2 mm, fused to halfway; anthers oblong, 2.1-3.1 mm, apex convex. Pistillate flowers: pedicel 1.5-2.5 cm; tepals 4-6, white, outer 2 broadly elliptic to elliptic, 1.2-1.9 × 0.8-1.2 cm, abaxially minutely hairy, inner 2 elliptic to obovate, 1.1-2 cm × 5-14 mm; ovary densely minutely hairy when young, 4-loculed; placentae axile, aberrant; styles 4, branched; stigmas 2-cleft, spiraled. Fruit berrylike, ellipsoidal, indehiscent, pendulous, ca. 1.3 × 1.8-1.9 cm, lacking ridges or wings or with up to 4 unequal, triangular, blunt ridges, apex with beak to 4 mm. Fl. Mar-May, fr. Apr-May. 2n = 22*.
● Primary tropical forests, shaded moist environments in valleys and along streams; 500-800(-1200) m. S and SW Yunnan.
Begonia silletensis subsp. silletensis occurs in Bangladesh, NE India, Myanmar, and N Thailand.