Begonia koelzii R.Camfield, 2018

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 : 51-56

Begonia koelzii R.Camfield sp. nov. [sect. Platycentrum]

urn:lsid:ipni.org:names:77175032-1

Figs 33–35 ; Table 1

Diagnosis

Similar to B. macrotoma Irmsch. (1951: 41) in having lacerate leaves, but differs in having a larger lamina (20–40 cm long, not 12–15 cm) and female flowers with 4–6 (not 3) tepals.

Etymology

The epithet honours Walter N. Koelz (1895–1989), the American zoologist who collected the type.

Type

India, Nagaland, Takubama, 4 Sep. 1950, Koelz 26053 (holo-: MICH1225736 ).

Other material examined

INDIA: Manipur: Karong, 26 Oct. 1950, Koelz 26739 ( MICH 1225781). Nagaland: Naga Hills, Kojima, 26 Oct. 1885, Clarke 41163A ( K); Naga Hills, Zakhama, 22 Oct. 1949, Ward 18912 ( BM) .

Description

Rhizomatous, monoecious herb, 25–90 cm high. Rhizome: 10–15 mm wide, glabrous, internodes 15 –20 mm long. Stipules: ovate, 10–19 × 8–12 mm, glabrous, deciduous. Leaves: petiole 30–50 cm long, sparsely puberulous; lamina ovate to broadly ovate, basifixed, cordate, 20–40(–50) × 20–30 cm, asymmetric, upper surface green, sparsely strigose all over, denser near the margin, underside green to pale green, sparsely strigose, denser on the veins, venation palmate, midrib 16 –22(– 40) cm long; margin deeply lobed, with ca 6 major lobes with further smaller lobelets, irregularly serrulate, with sparse hairs; apex acuminate. Inflorescences: cymose, axillary or terminal, few; peduncle sparsely puberulous, branching 3–4 times, primary peduncle 30–60 cm long, secondary 5–10 cm, tertiary 1–3 cm, quaternary ca 1 cm, with 8– 12 female and 2– 6 male flowers; bracts ovate-orbicular, 9–15 × 6–11 mm, deciduous. Male flower: pedicel 12–20 mm long, glabrous; tepals 4, outer tepals ovate, 10–14 × 7–10 mm, pink, glabrous, margin entire; inner tepals oblong to narrowly obovate, 7–14 × 5–9 mm, pink, glabrous, entire; androecium with 60–90 stamens, symmetric; filaments 1–2 mm long, unequal, fused at base; anther oblong-cuneate to oblong-elliptic, 1–1.5 mm long, dehiscing through slits longer than half the length of the anther, not hooded, connective extended. Female flower: pedicel 12–15 mm long, glabrous; bracteoles present; tepals (4–)6, equal, ovate to elliptic, outer tepals 10–15 × 8–11 mm, pale pink, glabrous, margin entire, inner tepals similar but smaller; ovary 2-locular, placentae bifid; capsule ellipsoid, 6–8 × 3–6 mm, strigose along the base of the main wing otherwise glabrous, with one long oblong wing and two short triangular wings; styles 3, convoluted with ends twisted twice. Fruit: pedicel 20 –25 mm long, recurved; capsule ellipsoid, 12–15 × 4–6 mm, strigose near base of main wing otherwise glabrous; wings extending along the pedicel slightly, unequal; longest wing oblong-elliptic, 10 –30 × 5–15 mm; shortest wings triangular-oblong, 3–5 × 9–11 mm.

Distribution and phenology

Endemic to the Arakan Mountain Range, usually found growing on cliff faces; 1000–2100 m. Flowering: September to October; fruiting: October to November.

Conservation status

Data Deficient. The full distribution of B. koelzii in the Arakan mountains is unknown.

Remarks

The female flowers on the material we have seen of this species had 3 styles; allied species can have either 2 or 3 styles; hence we consider there is the potential for B. koelzii to also be polymorphic for style number, which may be revealed given more material. The size of the female flowers is based on measurements from unopened buds, and we would expect the mature flowers to be larger. The bulbils are seen on larger, older leaves and are quite commonly observed.

This species is allied to several others which share lacerate leaves; B. panchatharensis S.Rajbh. ( Rajbhandary et al. 2010) from Nepal and Bhutan, B. pedatifida H.Lév. ( Léveillé 1909) from Yunnan, B. shilendrae from Arunachal-Pradesh, B. rubropunctata S.H.Huang & Y.M.Shui ( Huang & Shui 1994) from Yunnan, B. macrotoma Irmsch. ( Irmscher 1951) from Yunnan and B. longialata K.Y.Guan & D.K.Tian ( Guan & Tian 2000) from Yunnan. Begonia koelzii is distinct from these in a number of vegetative and floral characters ( Table 1 ). Begonia macrotoma is recorded from Northeast India by Gu et al. (2007) but no specimens were seen during this revision to confirm this. Begonia longialata is reported by Gu et al. (2007) as endemic to Yunnan; however, photographs have been taken in Manipur, on route to Khayang from Ukhrul ( Macer 2013) of a caulescent plant with lacerate leaves which could potentially represent it in our study region; however, no herbarium material has been seen. Begonia shilendrae is the only other allied species currently known to occur within the study area, but their distributions do not overlap; B. shilendrae is known only from the type locality of Itanagar in Arunachal-Pradesh, whereas B. koelzii is recorded from Manipur and Nagaland.

Figures

Fig. 33. Map showing the location of B. koelzii R.Camfield sp. nov. specimens.

Fig. 34. Begonia koelzii R.Camfield sp. nov. A. Plant habit. B. Leaf. C. Bulbil. D. Young female flowers. E. Fruit. Photographs courtesy of Nick Macer, of a plant in Manipur.

Fig. 35. Illustration of B. koelzii R.Camfield sp. nov. A. Plant habit. B. Adaxial leaf surface. C. Abaxial leaf surface. D. Inflorescence. E. Style. F. Male flower. G. Stamens. H. Female buds. I. Female flower. J. Mature fruit. Drawn by Rebecca Camfield. A, H from photographs by Nick Macer. B–D, J from Koelz 267739; E–G, I from Koelz 26053; all MICH.