Begonia raoensis 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 : 33-34

Begonia raoensis M.Hughes sp. nov. § Reichenheimia

urn:lsid:ipni.org:names:77151651-1

Figs 2 , 16

Diagnosis

Begonia raoensis is similar in habit and leaf shape to mature plants of B. stictopoda Miq. (A.DC.), but differs in having petioles with red, erect hairs (not appressed fine brown hairs), hairy stipules and styles that are not as deeply forked and a stigmatic surface only once (not twice) spirally twisted. B. trichopoda Miq. ( Miquel 1856) has hairy petioles and a similar habit, but in B. raoensis the hairs are shorter on the petioles (c. 3 mm, not 6–9 mm) and not as dense, the peduncles are sparsely minutely puberulent (not densely hairy); also the leaves of B. raoensis are suborbicular with overlapping basal lobes (not broadly ovate with basal lobes not overlapping in B. trichopoda ).

Etymology

The epithet refers to the village Rao nearby the type locality.

Type

SUMATRA: West Sumatra, road to Padang, Rao, 600 m, 18 May 2007, Hughes & Girmansyah MH 1400 (holo-: BO; iso-: E).

Description

Erect acaulescent herb to 30 cm tall, on steep rock banks; stem rhizomatous, glabrous, internodes c. 5 mm long. Stipules persistent, triangular, c. 10 × 5 mm, hairy on the keel, apex filiform, hairy. Leaves: petiole 4–21 cm long, terete, with dense erect red hairs, hairs becoming fleshy towards the petiole apex, forming a ring; leaf lamina on young plants smaller and ovate, on mature plants larger and suborbicular, 10–26 × 7–18 cm, basifixed, base cordate, basal lobes overlapping on larger leaves, upper surface reddish green when young maturing to green, glabrous, lower surface glabrous apart from short scattered hairs on the veins; venation palmate with 9 main veins, veins prominent on the upper surface; margin subentire, denticulate with evenly spaced small stiff red teeth, sparsely hairy; apex acute. Inflorescences axillary, total length c. 20 cm, cymose, protandrous, branching c. 5 times, with up to c. 40 flowers in larger plants, primary peduncle 12–17 cm long, sparsely minutely puberulent; bracts caducous, elliptic, 4 × 1.5 mm, margin entire. Male flowers: pedicel c. 6 mm long, glabrous, pink; tepals 4, white, glabrous, outer tepals 2, membranous, orbicular-ovate, 8 × 7 mm; inner 2 elliptic-obovate, 8 × 3 mm; androecium yellow, globose, on a short column; stamens c. 50; filaments 0.5 mm long, subequal; anthers 0.5 mm long, obtriangular, apex retuse, dehiscing through lateral slits that run the whole length of the anther. Female flower: pedicel 7–21 mm long, glabrous; ovary pale pink, glabrous, 9 × 15 mm in total including wings; capsule 3-locular, ellipsoid, 7 × 6 mm, placentae unknown; wings 3, subequal, rounded-triangular, largest wing 5 mm wide; tepals 3–4, white; outer 2 tepals orbicular-ovate, 7 × 6 mm, glabrous; inner 1-2, elliptic, 6 × 2 mm; stigmas 3, free, deep yellow, shallowly forked, stigmatic surface once spirally twisted. Fruit: pendent on a 2 cm long hair-like pedicel, shape as same as the ovary, c. 9 × 16 mm; apex obtuse.

Distribution and habitat

Only known from the type collection from a steep soil bank with some surface water and overhanging roadside scrubby vegetation in West Sumatra near Rao village ( Fig. 2 ).

Conservation status

The forest in the area is quite fragmented, and it would seem that the species is able to persist in these fragments. The area is not well collected and we know little about the distribution of the species, which we consider to be Data Deficient ( IUCN 2012).

Figures

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

Fig. 16. Begonia raoensis M.Hughes sp. nov. A. Habit. B. Inflorescence in female phase (scale bar = 1 cm). Photographs from the Rao vicinity, of the type Hughes & Girmansyah MH1400.