Volume 14 > Part 3 > Year 2019 > Page 380 > Begoniaceae > Begonia

15. Begonia fibrosa C.B.Clarkewfo-0000823997

[§ Reichenheimia], Fl. Brit. India 2: 652. 1879; Craib, Fl. Siam. 1: 773. 1931; Hughes, Annot. Checkl. SE Asian Begonia. 39. 2008. Plate XXXVI: D–E.

Accepted Name : This is currently accepted.

Description : Monoecious caulescent herb ca 20 cm tall. Stems tuberous, globose with numerous fibrous roots, 4−5 mm diam., aerial stem pale green, glabrous, brown when dry, 4−12 cm long. Leaves sessile, 1–2 per plant, alternate; lamina basifixed, succulent, chartaceous when dry, symmetric, adaxial glabrous, light bright green or greenish yellow, abaxial pale green, orbicular or suborbicular, 4−15 by 5−16 cm, base cordate, margin crenate, venation palmate, veins 4−7, prominent beneath. Stipules not seen. Inflorescences terminal, paniculate, branching 1–3 times, bisexual, 20−30 cm long, staminate flowers basal, pistillate flowers distal, protandrous; peduncles pale green, 10−18 cm long, terete, densely covered with multicellular glandular hairs, glossy. Bracts leafy, orbicular. Staminate flowers: pedicels pale green or pale pink, 10−15 mm long, densely hairy, erect; tepals 2, white near centre and with a pale pink outline, outer parts bright pink, orbicular, 4−5 by 5−6 mm, base slightly rounded, apex rounded, margin entire, outer parts densely hairy, inner parts glabrous; androecium zygomorphic, stamens 10, bright yellow, filaments fused at base, ca 1 mm long, anthers oblong, ca 1 mm long, dehiscing by short slits near tip. Pistillate flowers: pedicels pale green, 7−10 mm long, densely hairy; tepals 2(–3), same colour as staminate flower, orbicular, 6−7 by 6−7 mm, base rounded, apex rounded, margin entire, outer parts densely hairy, inner parts glabrous; styles 3, fused at base, dark yellow, stigmatic band crescent-shaped, minutely papillose; ovary green or pink with 3 unequal wings, 3-locular, placentae unilamellate. Fruit a dehiscent capsule, drying pale brown, ca 10–15 by 4−5 mm; locules ovate, 4−5 by 4−5 mm, abaxial wing deltate, ca 10 mm long, 5−6 mm at base, 2 lateral wings narrower, curved along length of capsule, ca 3 mm long, 5−6 mm wide at base. Seeds brown, barrel-shaped.

Thailand : NORTHERN: Chiang Rai.

Distribution : Myanmar (type).

Ecology : On shaded limestone cliffs with water seepage in mixed deciduous forests, 380−930 m alt. Flowering: August–September; fruiting: September–December.

Vernacular : Dat bua nuea (ดาดบัวเหนือ).

Notes: Begonia fibrosa resembles B. prolifera in the round leaf shape and the inflorescence arising at the leaf sinus. However, B. fibrosa differs in having multicellular glandular hairs, two tepals in staminate flowers, three stigmas and three-locular ovaries. Begonia prolifera is glabrous, has four tepals in staminate flowers and two-locular ovaries with 2 stigmas.