Begonia brevicaulis

Camfield, Rebecca & Hughes, Mark, 2018, A revision and one new species of Begonia L. (Begoniaceae, Cucurbitales) in Northeast India, European Journal of Taxonomy 396, pp. 1-116 : 24-26

Begonia brevicaulis A.DC. [sect. Parvibegonia]

Figs 14–15

Annales des Sciences Naturelles; Botanique, Sér. 4, 11: 135 (de Candolle 1859). – Type: India, Meghalaya, Khasi Hills, Tyrna, 23 Aug. 1850, Hooker & Thomson 26 (lecto-: K000634621, here designated).

Citations in other publications

de Candolle (1864: 350), Clarke (1879: 647), Clarke (1881: 119), Uddin (2007: 593).

Other material examined

INDIA: Meghalaya: Khasi Hills, Cherrapunji, 6 Jul. 1952, Chand 6007 ( MICH); ibid., 6 Jun. 1952, Chand 5819 ( MICH); ibid., 14 Oct. 1886, Clarke 45351B ( BM); ibid., 7 Jul. 1952, Koelz 30496 ( MICH); ibid., 8 Jun. 1952, Koelz 30224 ( MICH); ibid., 29 Jul. 1952, Koelz 30887 ( MICH); Khasi Hills, Tyrna to Churra, 26 Aug. 1850, Hooker & Thomson 26 ( K).

Description

Tuberous, erect, monoecious herb, 5–15 cm high. Stem: 2–4 mm wide, sparsely pilose to glabrous, internodes 2–4 cm long. Stipules: lanceolate, 1–5 × 1–2 mm, puberulous on reverse, semi-persistent. Leaves: petiole 2–8(–12) cm long, sparsely pilose to glabrous; lamina oblong-ovate to broadly ovate, basifixed, base shallowly cordate to truncate, lobes not overlapping, 2–19 × 1.5–14 cm, symmetric to slightly asymmetric, upper surface pale matt green, sparsely hirsute to glabrous, underside pale green or red-purple, sparsely puberulous hairs mostly on veins, venation palmate, midrib 1.5–11 cm long; margin entire, shallowly undulate, with very sparse short hairs; apex acute. Inflorescence: cymose, terminal and axillary, few; peduncle with puberulous hairs, branching twice, primary 3–6 cm long, secondary 9–11 mm long, 1– 2 female and 2– 3 male flowers; bracts not seen. Male flower: pedicel 5–30 mm long, sparsely pilose to glabrous; tepals 4; outer tepals broadly obovate to sub-orbicular, 5–10 × 4–7 mm, white, densely white pilose on reverse, margin entire; inner tepals narrowly elliptic to lanceolate, 3–9 × 1–2 mm, white, glabrous; androecium with 15–30 stamens, symmetric; filaments 1 mm long, equal, slightly fused at base into a short column; anther narrowly elliptic, 1.5–2 mm long, dehiscing through slits longer than half the length of the anther, not hooded, connective markedly extended. Female flower: pedicel 5–30 mm long, puberulous; bracteoles absent; tepals (4–)5, subequal, oblong-ovate, outer tepals 2, 5–9 × 3–4 mm, white, white-pilose on reverse, inner tepals 2(–3), smaller and glabrous; ovary 2-locular, placentae bifid; capsule oblong-ellipsoid, white pilose, with one long rounded-triangular wing and two short rounded wings; styles 3, deeply forked once and twisted once, deciduous or persistent. Fruit: recurved 7–13 × 12–26 mm; capsule oblong-ellipsoid, 4–11 × 3–7 mm, sparsely white pilose; wings extending along the pedicel slightly, unequal; longest wing rounded oblong, 8–16 × 7–13 mm; shortest wing crescent-shaped to triangular, 1–3 × 5–7 mm.

Distribution and phenology

Hills and valleys near Cherrapunji and Tyrna in Meghalaya, India and Sikkim; 450–1200 m. Flowering: June to August; fruiting: July to August.

Conservation status

Data Deficient. Based on material from the study area only B. brevicaulis would meet the criteria for Critically Endangered due to the degradation of habitat around the type locality and the fact that the species has not been collected since 1952. However, specimens at E, collected by G.H. Cave in 1915 and 1917 (E00300429, E00157125) potentially expand the distribution to Sikkim, but their precise locality is unknown. The type locality is near the Cherrapunji-Mawsynram Reserve Forest along with several other national parks and reserves in which the species could reside.

Remarks

Begonia brevicaulis is one of two species in Begonia sect. Parvibegonia in the region, the other being B. wattii . Begonia brevicaulis is easily distinguished in having a distinctive extended connective on the stamens, 3 styles (not 2), a rounded (not acute) larger wing on the fruits, more symmetric leaves with an undulate (not serrulate) margin, and plant being generally less hairy.

The type material is annotated as being collected from ‘Terya to Churra’ which is mentioned in Hooker’s travel diaries ( Hooker 1854). The diary refers to staying in Churra Pooji or Churra village, now known as Cherrapunji or Sohra. To the south is a neighbouring village called Tyrna, perhaps the ‘Terya’ annotated on the specimen.

The species is known from relatively few specimens in addition to the type material collected in 1850. Cave made a collection 65 years later from Sikkim, the exact location of which is unknown. The label states the locality as Tista which probably refers to the River Tista which runs through Sikkim into West Bengal, joining the Brahmaputra near the Khasi Hills. Koelz and Chand collected the species again from the type locality 100 years after Hooker.

Figures

Fig. 14. Map showing the location of B. brevicaulis A.DC. specimens.

Fig. 15. Illustration of B. brevicaulis A.DC. A. Habit of plant. B. Male flower. C. Stamen. D. Selection of stamens. E. Mature fruit. F. Adaxial leaf surface. G. Abaxial leaf surface. H. Style. I. Female flower. J. Seed. K. Cross-section of fruit. L. Side view of female flower. Drawn by Rebecca Camfield. A–D, F–G from Chand 5819; E, J–K from Koelz 30496; H–I, L from Koelz 30887; all MICH.