Begonia formosana (Hayata) Masam.

Herbs. Rhizomes elongate, to 1.9 cm in diam. Stems erect, 35-95 cm tall, glabrous or subglabrous. Leaves basal and cauline; stipules caducous, ovate to very broadly ovate, to 2.5 × 1.8 cm; petiole 7-43 cm, glabrous or subglabrous; blade ovate to broadly ovate, asymmetric, 9-25 × 11-29 cm, abaxially sparsely scaberulous, adaxially subglabrous, venation palmate, 7-11-veined, base oblique, cordate, margin irregularly denticulate, shallowly divided, apex acuminate. Inflorescences to 23 cm, subglabrous; peduncle 6-13 mm; bracts caducous, triangular or broadly ovate, to 2.1 × 1.5 cm, thickly papery. Staminate flowers: pedicel 8-14 mm; tepals 4, white to pinkish, glabrous, outer 2 broadly obovate to orbicular, 1.2-2.6 × 1.1-2.5 cm, inner 2 oblanceolate to narrowly obovate, 1.1-2.3 cm × 5-13 mm; stamens 82-124; filaments 1.9-3.1 mm; anthers narrowly obovoid, 1.8-2.2 mm. Pistillate flowers: pedicel 8-14 mm; tepals 5 or 6(-10), unequal, narrowly obovate to very broadly obovate, largest 1.1-2.6 × 0.9-2.4 cm, smallest 1-2.3 cm × 5-11 mm; ovary glabrous, 2-loculed; placentae axile, bilamellate; styles 2, fused at base; stigmas 2-cleft, spiraled. Capsule nodding, unequally 3-winged; abaxial wing triangular, 1-2.3 cm; lateral wings smaller. Fl. Jun-Oct, fr. Aug. 2n = 60, 64*.

Taiwan [Japan (Ryukyu Islands)].

Forests, shaded moist environments; 700-900 m.

Begonia laciniata Roxburgh var. formosana Hayata, J. Coll. Sci. Imp. Univ. Tokyo 30(1): 124. 1911; B. formosana f. albomaculata T. S. Liu & M. J. Lai; B. tarokoensis M. J. Lai.