Begonia wengeri C.E.C.Fisch. [sect. Diploclinium] Figs 63, 64A Bulletin of Miscellaneous Information, Kew 1932: 200 (Fischer 1932). – Type: India, Mizoram, Lungleh, Aug. 1831, Wenger 324 (lecto-: K000634614, here designated; isolecto-: K000820109). Citations in other publications Fischer (1938: 98), Uddin (2007: 595). Description Tuberous, erect, monoecious herb, 10–20 cm high. Stem: slender, 2–3 mm wide, red-brown tomentose, internodes 2–4 cm long. Stipules: lanceolate, 3–4 × 1–2 mm, sparsely tomentose, persistent. Leaves: petiole 1.5–4 cm long, tomentose; lamina ovate-orbicular, basifixed, base cordate with lobes not overlapping, 2–6.5 × 2–6 cm, slightly asymmetric, upper surface dark green, sparsely red hispid all over, underside green, red tomentose on veins only, venation palmate, midrib 1.5–5 cm long; margin crenate, with hairs; apex acute. Inflorescence: cyme to a raceme of cymes, axillary to terminal, few; peduncle red puberulous, branching 2–3 times, primary 9–14 mm long, secondary 3–6 mm long, tertiary 1–2 mm long, with 2– 4 female and 4– 6 male flowers per cyme; bracts ovate, 3–4 × 2 mm long, margin dentate, with hairs, persistent. Male flower: pedicel 3–8 mm long, red puberulous; tepals 4; outer tepals broadly obovate to ovate-orbicular, 3–4 × 3 mm, white, puberulous on reverse, margin entire; inner tepals oblanceolate, 2–3 × 1 mm, white, glabrous; androecium with 8–12 stamens, symmetric; filaments 0.2 mm long, subequal, fused at base into a short column; anther elliptic-globose to oblong, 1 mm long, dehiscing through short slits near the tip, not hooded, connective extended slightly. Female flower: pedicel 5 mm long, red puberulous; bracteoles present, 1–2, spaced from the ovary; tepals 6, equal, oblong elliptic to obovate, 2–4 × 1–2 mm, white, sparsely puberulous on reverse to glabrous, inner tepals similar yet smaller and glabrous; ovary 2-locular, capsule oblate 2 × 1 mm, tomentose, with one long oblong wing and two very small oblong wings; styles 2, shallowly forked once, caduceus. Fruit: pendulous; capsule oblate 4–6 × 2–3 mm, sparsely red puberulous to glabrous; wings extending along the pedicel, longest wing broad oblong, 6–8 × 8–10 mm; shortest wings broad oblong, 4–3 × 9– 6 mm. Distribution and phenology Endemic to the hills about Lungleh; 450– 650 m. Flowering and fruiting: around August. Conservation status Data Deficient. Known only from the type collection, near to one of the main roads through Mizoram. Remarks Begonia wengeri is known only from the type collection, but has distinct fruit which distinguish it from the vegetatively similar B. surculigera Kurz (Kurz 1871) from Myanmar, which has been considered synonymous by some authors (Kumar 2002; Dash 2010). However the fruits are very different (Fig. 64); those of B. surculigera have wings that are small, rounded and extended basally, whereas B. wengeri has fruit almost twice the size with wings that are apically broader and oblong. Both species have cordate leaves but those of B. wengeri have scattered red hairs on the upper surface (as well on pedicels, tepals and ovary) with a hairy, crenate margin. Begonia surculigera has glabrous leaves (and flowers) with an entire margin. The stamens also differ with B. surculigera having 8 anthers which are obovate with a connective that is barely extended, whereas B. wengeri has up to 12 anthers that are narrowly oblong with a conical extended connective. Begonia wengeri shares a terminal racemose inflorescence with the allied B. lushaiensis and B. pedunculosa, however, the three are easily distinguishable based on leaf shape.

Published as part of Camfield, Rebecca & Hughes, Mark, 2018, A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India, pp. 1-116 in European Journal of Taxonomy 396 on pages 100-102, DOI: 10.5852/ejt.2018.396, http://zenodo.org/record/3787049