Begonia beludruvenea M.Hughes, 2015

Hughes, Mark, Girmansyah, Deden & Ardi, Wisnu Handoyo, 2015, Further discoveries in the ever-expanding genus Begonia (Begoniaceae): fifteen new species from Sumatra, European Journal of Taxonomy 167, pp. 1-40 : 7-8

Begonia beludruvenea M.Hughes sp. nov. § Bracteibegonia

urn:lsid:ipni.org:names:77151638-1

Figs 1 , 2

Diagnosis

The velvety red hairs on the stem and veins are distinctive. B. beludruvenea is nearest to B. verecunda M.Hughes ( Hughes et al. 2009) from Gunung Leuser National Park in terms of its habit and leaf shape, but the hairs are denser and fleshier, the male flowers are slightly larger (10–14 mm diameter, not c. 9 mm) and have 2 (not 4) tepals, and the styles are longer in the female flowers (c. 5 mm, not 3–4 mm). B. verecunda has not been recorded from limestone, whereas B. beludruvenea is a limestone endemic.

Etymology

The epithet is derived from the Indonesian word for “velvet”, beludru, referring to the dense red hairs on the veins.

Type

SUMATRA: West Sumatra, Bukit Sebelah, 400 m, 22 Jul. 2009, Hughes & Taufiq MH 1541 (holo-: BO; iso-: E).

Additional material

SUMATRA: West Sumatra, Bukit Sebelah, 350 m, 20 May 1983, Pannell 1860 ( BO); ibid., 450 m, 23 Jul. 2009, Hughes & Taufiq MH 1549 A ( BO, E).

Description

Erect low-growing caulescent herb c. 15 cm tall; stem strigose with red fleshy hairs, internodes 1–2 cm long. Stipules persistent, hairy at the base, c. 10 mm long, elongate lanceolate, apex ending in a fine hair. Leaves: petiole 4–15 mm long, terete, red strigose; lamina obovate-oblong to elliptic, asymmetric, 6–9 × 2–4.5 cm, basifixed, base cordate, oblique, lobes overlapping slightly, larger lobe auriculate; upper surface dark green, sometimes with a blue iridescence, glabrous or with sparse evenly spaced bristles between the veins; underside paler green, red strigose on the veins; venation pinnate-palmate; margin dentate-crenate, apex obtuse to acute. Inflorescence terminal, total length c. 5 cm, a compressed cyme, appearing fasciculate, protandrous, with c. 4 flowers, 2 male and 2 female; primary peduncle 1.5–2.5 cm, with short white hairs; bracts persistent, lanceolate, 2–7 mm long, margin denticulate, apex acute. Male flower: pedicel c. 15 mm long, white, with short white hairs; tepals 2, sub-orbicular, based cordate when young, truncate when open, white, 10 × 12–14 mm, minutely denticulate to entire, sparsely puberulous on the veins, apex rounded or obtuse; androecium yellow, symmetric, a loose fascicle, slightly asymmetric, shorter stamens uppermost; stamens 25–30, filaments fused at the base into a short column, unequal, 1.5–2 mm; anthers oblong, subequal, 1.5–2 mm, hooded, apex retuse, dehiscing through slits about ⅔ the length of the anther. Female flower: pedicel 5–9 mm long, pale green, sparsely hairy; ovary pinkishwhite, hairy on the capsule and wing edge, triangular, total size 10 × 8 mm including the wings; capsule ellipsoid, 9 × 2–3 mm, 3-locular, placentae entire; wings subequal, 2–3 mm wide; tepals 5, obovateelliptic, pale pink in bud, white when open, 7–10 mm long, outer 3 denticulate, sparsely puberulent, 5 mm wide, inner 2 entire, glabrous, 4 mm wide, tepals closing and turning green after pollination and during fruit maturation; stigmas 3, free, Y-shaped, stigmatic surface once spirally twisted. Fruit recurved on a stiff pedicel c. 10 mm long, total size 13 × 10 mm including the wings, larger wing 13 × 3 mm and more rounded at the base than the 2 smaller ones, 2 smaller wings 10 × 3 mm; apex truncate.

Distribution and habitat

Endemic to the Bukit Sebelah limestone in West Sumatra ( Fig. 2 ), where it grows on steep, shaded clay soil banks over the limestone base rock.

Conservation status

The bulk of the distribution lies within the Bukit Sebelah and Batang Pangean protection forest which is likely to represent its full natural range. Although there is low level disturbance around the forest tracks, the reserve is reasonably intact and populations of B. beludruvenea can colonise previously disturbed bare soil banks. Although naturally rare, following IUCN (2012) we consider the species as Least Concern as long as the reserve is well managed.

Figures

Fig 1. Begonia beludruvenea M.Hughes sp. nov. A. Habit. B. Inflorescence with two male flower buds and two female buds beneath. C. Female flower. D. Habit showing blue iridescence. E. Male flower. F. Underside of leaf margin showing red hairs. C–E from Bukit Sebelah, Hughes & Taufiq MH1549A; A, B, F from Bukit Sebelah, Hughes & Taufiq MH1541. Scale bars on insets: B, C, E, F = 1 cm; D = 5 cm.

Fig. 2. Map of Sumatra showing the full known species distributions based on collection localities. Each point may represent more than one collection.