Begonia (sect. Platycentrum) hatacoa Buch.
Creators: name: Camfield, Rebecca
name: Hughes, Mark
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Cucurbitales
Begoniaceae
Begonia
Begonia hatacoa

description: Begonia hatacoa Buch. -Ham. ex D.Don [sect. Platycentrum]
Figs 28–29
Prodromus Florae Nepalensis: 223 (Don 1825).
– Type: Nepal, Sembu, 8 Jul. 1802, Buchanan-Hamilton (lecto-: BM000521516, here designated).
Begonia rubrovenia Hook., Botanical Magazine 79: 4689 (Hooker 1853). – Platycentrum rubrovenium (Hook.) Klotzsch, Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin: 244 (Klotzsch 1855 [‘1854’]).
– Type: Cultivated specimen, grown by Nuttall in Preston, UK, from material collected in East Bhutan, Booth s.n. (lecto-: K000739936, here designated).
Citations in other publications
As B. hatacoa: Hara (1972: 143), Hara (1975: 85), Hara et al. (1979: 181), Grierson (1991: 243), Chauhan (1996: 175), Chauhan (2000: 424), Kumar (2002: 644), Gu et al. (2007: 178), Uddin (2007: 594), Hughes (2008: 49), Dash (2010: 34), Morris (2011e: 214), Verma et al. (2013: 179), Baruah & Choudbury (2014: 41); as B. rubrovenia Koch (1858: 341), de Candolle (1864: 347), Clarke (1879: 645), Clarke (1881: 119), Gagnepain (1921: 1102), Craib (1931: 778), Fischer (1938: 98), Deb (1961: 285), Deb (1981: 269); as Platycentrum rubrovenium: Klotzsch (1855 [‘1854’]: 124), de Candolle (1864: 347), Hara (1972: 143).
Description
Rhizomatous, monoecious herb, some portions of stem erect, 8–35 cm high. Rhizome: ca 10 mm wide, glabrous, internodes 8–10 mm long. Stem: slender, 2–11 mm wide, dense to sparsely puberulent, internodes on erect stem, 5–15 cm long. Stipules: lanceolate, 5–24 × 2–6 mm, pubescent, persistent. Leaves: petiole 4–15(–20) cm long, tomentose to subglabrous; lamina ovate to lanceolate to linear, basifixed, base cuneate to rounded, (4–)9–20 × 3–10(–15) cm, slightly asymmetric to asymmetric, upper surface dark green with white spots between the veins or dark green without spots, glabrous or puberulous on the veins near petiole attachment, underside red-purple, sparsely to densely puberulous on veins mostly, venation pinnate to palmate-pinnate, midrib (3.5–) 8–19 cm long; margin entire to denticulate to shallowly broadly dentate, glabrous; apex acuminate. Inflorescence: cymose, terminal or axillary, few; peduncle glabrous, branching 2–3 times, primary 5–15 cm, secondary 1–3 cm, with 4– 6 female and 4– 8 male flowers; bracts lanceolate to ovate with an extended tip, 12–20 × 8–10 mm, margin entire, persistent. Male flower: pedicel 5–15 mm long, glabrous; tepals 4; outer tepals obovate, 5–13 × 3–7 mm, white to pale pink, with dark pink veins, glabrous, margin entire; inner tepals oblong or elliptic, 5–12 × 2–6 mm, white to pale pink, glabrous; androecium with 30 –60 stamens, symmetric; filaments 1–2 mm long, unequal; anther narrowly elliptic, 2 mm long, dehiscing through slits longer than half the length of the anther, not hooded, connective extended. Female flower: pedicel 11–36 mm long, glabrous; bracteoles absent; tepals 4–5, equal, obovate, outer tepals 8–12 × 5–7 mm, white to pale pink, with darker veins, glabrous, inner tepals similar but smaller; ovary 2-locular, placentae bifid, capsule ellipsoid, glabrous, with one long triangular wing and two short oblong wings; styles 2, deeply forked once and twisted once, deciduous. Fruit: recurved; capsule ellipsoid, 6–14 × 2–8 mm, glabrous; wings extending along the pedicel slightly, subequal; longest wing triangular to rounded oblong, 10– 20(–27) × 5–13 mm; shortest semi-circular, 3–7 × 8–13 mm.
Distribution and phenology
Arunachal-Pradesh, Assam, Meghalaya, Mizoram and Manipur; also in China, Nepal, Sikkim, Bhutan, Myanmar, Thailand and Vietnam; 600–1850 m. Flowering: mainly from June to September (but can flower at any time of the year); fruiting: mainly between August and November.
Conservation status
Least Concern. Begonia hatacoa has an AOO of 132 km 2 and an EOO of 416,730 km 2. This species is widespread and common throughout continental eastern Asia.
Remarks
This is a variable species in leaf shape and colour but the flowers are characterized by having dark pink veins on the outer tepals. These stripes appear darker on the buds and fade as the flower ages; occasionally you get pure white flowers.
Key to varieties:
1. Leaves ovate and asymmetric, margin entire, underside with scattered hairs mostly on veins ................................................................................................................................ var. hatacoa
– Leaves linear and symmetric, margin wide spaced shallow dentate, underside with dense hairs on veins................................................................................................................................. var. meisneri
description: 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 43-45, DOI: 10.5852/ejt.2018.396, http://zenodo.org/record/3787049