Begonia roxburghii

Begonia roxburghii (Miq.) A.DC. [sect. Sphenanthera] Figs 52–53 Prodromus Systematis Naturalis Regni Vegetabilis 15 (1): 398 (de Candolle 1864). – Diploclinium roxburghii Miq., Flora van Nederlandsch Indie 1 (1): 692 (Miquel 1856). – Type: Bangladesh, Chittagong, Hooker & Thomson 40 (lecto-: K000634807; isolecto-: K). Casparya oligocarpa A.DC., Annales des Sciences Naturelles; Botanique, Sér. 4, 11: 118 (de Candolle 1859). – Type: Northeast India, Meghalaya, Khasia, 610–1210 m, Hooker & Thomson 40 (lecto-: K000761501, here designated; isolecto-: BM, K). Casparya polycarpa A.DC., Annales des Sciences Naturelles; Botanique, Sér. 4, 11: 118 (de Candolle 1859). – Type: India, Meghalaya, Assam, Assam Plains, Griffith s.n. (lecto-: K, here designated; isolecto-: K). Begonia malabarica auct. non Lam.: Roxburgh in Flora Indica 3: 648 (Roxburgh 1832). Citations in other publications As B. roxburghii: Clarke (1879: 635), Clarke (1881: 115), Gagnepain (1921: 1119), Kanjilal (1938: 333), Fischer (1938: 98), Deb (1961: 285), Hara et al. (1979: 182), Deb (1981: 269), Grierson (1991: 243), Chauhan (1996: 176), Chauhan (2000: 427), Kumar (2002: 651), Kress et al. (2003: 172), Tebbitt (2005: 207), Uddin (2007: 594), Hughes (2008: 111), Khatun (2008: 11), Dash (2010: 39), Das et al. (2013: 236), Verma et al. (2013: 179); as Diploclinium roxburghii: de Candolle (1864: 399); as Casparya oligocarpa: de Candolle (1864: 276), Clarke (1879: 635); as Casparya polycarpa: de Candolle (1864: 277), Kurz (1871: 295). Other material INDIA: Arunachal-Pradesh: Mishmi Hills, 22 Apr. 1949, Ward 18528 (BM); Pango to Ninguing, Rao 17667 (ASSAM n.v.); Tidding Valley, Theronhaing, 8 Mar. 1928, Ward 7934 (K); ibid., 8 Feb. 1950, Ward 19131 (BM); Tuting to Kapu, Rao 17416 (ASSAM n.v.). Assam: Upper Assam, 1841, Hooker 515 (K); Assam, Beddome 3194 (BM); Cachar, Khozungma, 2 Jun. 1951, Chand 4672 (MICH). Manipur: Koupru, Deb 2340 (CAL n.v.); ibid., Deb 2340 (CAL n.v.). Meghalaya: Garo Hills, Tura Mountain, 1929, Parry 866 (K); Jaintia Hills, Apr. 1968, Yandell 45 (K); Khasi Hills, Jul. 1879, Mann s.n. (ASSAM n.v.); Khasi Hills, Barapani, 16 Jun. 1949, Koelz 22985 (MICH); Khasi Hills, Cherrapunji, 4 Aug. 1952, Chand 6293 (MICH); ibid., 6 Jul. 1952, Chand 5998 (MICH); ibid., 18 Jul. 1952, Chand 6158 (MICH); ibid., 23 Jul. 1952, Koelz 30791 (MICH); Khasi Hills, Jyrna, 2 Oct. 1867, Clarke 5462 (K); Khasi Hills, Mawryngkneng, 4 Sep. 1951, Koelz 28338 (MICH); Khasi Hills, Nongphoh, 2 May 1949, Koelz 22620 (MICH); Khasia, Hooker & Thomson 40 (K); ibid., 610–1210 m, Hooker & Thomson s.n. (K); Shillong, 1 Aug. 1886, Clarke 44383 (K); ibid., 1 Aug. 1886, Clarke 44383C (BM). Mizoram: Hmuifang, Aug. 1929, Parry 264 (K); Lushai Hills, Jul. 1927, Parry 186 (K); Lushai Hills, Kaultan, Jul. 1929, Parry 186 (K). Nagaland: Naga Hills, Digboi, 5 Jan. 1936, Barnard B1A3 (BM 000017299); Naga Hills, Henima, 19 Sep. 1935, Bon 6477 (K). Tripura: Sardukchara, Deb 1484 (CAL n.v.); Tlangsang, Deb 27175 (CAL n.v.). Description Caulescent, erect, dioecious herb, 60–120 cm high. Stem: slightly woody, stout, 5–20 mm wide, glabrous, internodes 5–13 cm long. Stipules: lanceolate, 14 –17 × 3–6 mm, glabrous, deciduous. Leaves: petiole 5–15(–26) cm long, glabrous; lamina ovate to broadly ovate, basifixed, base cordate with lobes not overlapping, (5–)15–30 × 5–23 cm, asymmetric, upper surface green, glabrous, underside green, glabrous, venation palmate-pinnate, midrib 4–24 cm long; margin entire to denticulate, glabrous; apex acuminate. Inflorescence: cymose, axillary, many; peduncle puberulous; male branching 2–3 times, primary 2–5 mm long, secondary 1–2 mm long, tertiary up to 1 mm long, 8–10 flowers; female branching twice, primary 10–16 mm long, secondary 4–6 mm long, 2–5 flowers; bracts ovate, 10–13 × 3–4 mm, glabrous, margin entire. Male flower: pedicel 8–30 mm long, glabrous; tepals 4; outer tepals ovate to oblong-elliptic, 9–12 × 4–6 mm, white to pink, glabrous, margin entire; inner tepals elliptic, 6–12 × 2–5 mm, white to pink, glabrous; androecium with 40 –65 stamens, symmetric; filaments 2 mm long, fused at base; anther oblong elliptic, 1–2 mm long, dehiscing through slits longer than half the length of the anther, not hooded, connective extended. Female flower: pedicel 7–17 mm long, glabrous to puberulous; bracteoles absent; tepals 4(–6), equal, obovate, 7–13 × 3–10 mm, white to pale pink, glabrous, margin entire, inner tepals similar but smaller; ovary 4-locular, placentae bifid; capsule pyramidal-ovoid, 3–5 × 4–7 mm, puberulous, without wings, with 4 horn-like projections; styles 4, deeply forked once and twisted twice, persistent. Fruit: pendulous; capsule pyramidal-ovoid, 18 × 16 mm, glabrous to sparsely puberulous. Distribution and phenology Northeast India; also in Nepal, Sikkim, Bangladesh and Myanmar; 300–1850 m. Flowering: February to October; fruiting: July to October. Conservation status Least Concern. Begonia roxburghii has an AOO of 96 km 2 and an EOO of 277,400 km 2 with ample suitable habitat. The species has been found near Dibang Wildlife Sanctuary, and within the Lengteng Wildlife Sanctuary, Nongkhyllem Wildlife Sanctuary and Namphada Forest Reserve. Remarks The closest ally to B. roxburghii in the study area is B. silletensis, but the former is distinct in having a main stem and inflorescences in the leaf axils, not on peduncles arising from the rhizome. The species is completely glabrous apart from occasionally some small hairs on the inflorescences, again unlike B. silletensis which has fine hairs on petioles and leaves. It is possible for natural hybrids to occur with species of B. sect. Platycentrum, as represented by Ward 19131 (BM). This collection bears female flowers in clusters in the leaf axils with small wings. It was initially determined as B. dux but the flowers are rather small and the specimen is best interpreted as a hybrid of B. roxburghii.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 81-84, DOI: 10.5852/ejt.2018.396, http://zenodo.org/record/378704