Begonia filiformis Irmsch.

Herbs. Rhizomes creeping, tortuous, 0.7-1.5 mm in diam. Leaves all basal; stipules caducous, triangular, 0.5-1 × 0.5-0.7 cm, apex awned; petiole 5-15 cm; blade adaxially green, with white spot between veins, obliquely ovate to suborbicular, 9-22 × 9-14 cm, papery, abaxially woolly-villous, more densely so on veins, adaxially papillose-tomentose or setose-tomentose, venation palmate, 7-veined, tertiary veins weakly percurrent, base deeply cordate, margin shallowly and densely serrate, apex acuminate or shortly caudate. Inflorescences axillary; peduncle 22-40 cm, glandular hispid; bracts oblong-lanceolate, 4-7 × 1.1-1.5 mm, margin long ciliate or serrate-ciliate, apex awned. Staminate flowers: pedicel 1-2.3 cm, glandular hispid; tepals 4, outer 2 ovate or suborbicular, 8-12 × 7-8 mm, adaxially glandular hispid, apex acute or rounded, inner 2 oblong, 5-7 × 2.2-2.6 mm, apex rounded; stamens numerous; filaments ca. 1.5 mm; anthers obovoid, 0.5-0.8 mm, apex ± emarginate. Pistillate flowers: pedicel 1.5-3 cm, glandular hispid; tepals 3, outer 2 broadly ovate, 7-10 × 8-10 mm, adaxially glandular hispid, inner 1 oblong, 5-6 × 2.2-2.8 mm; ovary elliptic, glandular hispid, 1-loculed; styles 3, fused at base; stigmas spiraled. Capsule nodding, unequally 3-winged; abaxial wing ligulate or lunate, 4-7.5 mm; lateral wings smaller, subtriangular or lunate. Fl. (Mar-)Apr-Jun, fr. May.

● On limestone rocks or in moist rocky caves of forest understories. Guangxi (Long’an, Longzhou).