Begonia kebuhoensis S.Julia & C.Y.Ling, 2022

Julia, S., Kiew, R. & Ling, C. Y., 2022, ADDITIONS TO THE BEGONIA FLORA OF SARAWAK, BORNEO, I: TWELVE NEW SPECIES AND A NEW RECORD, Edinburgh Journal of Botany 79 (410), pp. 1-46 : 15-17

6. Begonia kebuhoensis S.Julia & C.Y.Ling , sp. nov.

Among the ‘calcarea group’ of begonias ( Kiew et al., 2016), Begonia kebuhoensis is most similar to B. sadirensis Kiew & S.Julia in its habit and glabrous upper leaf surface, but it differs in its slightly bullate lamina when fresh, margin ciliate (versus lamina not bullate, margin minutely toothed); male flowers with 4 dimorphic tepals (versus 4 isomorphic tepals); smaller ovary, c.8–9 × 11 mm with rounded or truncate wings both distally and proximally (versus ovary c.12 × 18 m, wings narrowed proximally); and strongly recurved (versus straight) pedicel.

– Type: Malaysia, Borneo, Sarawak, Belaga District , Linau Forest Management Unit , Sungai Kebuho , 2°18′40′′N, 114°40′52′′E, 22 ix 2016, Ling et al. SFC 7012 (holotype SAR!, isotype KEP!). Figure 7 .

Robust creeping herb to 4.5–60 cm long, stem prostrate, rooting at nodes. Stems greenish, unbranched, succulent, 3–9 mm thick, sometimes with sparsely red or pale green hairs, hairs 2–3 mm long, internodes 0.5–4.5 cm long, slightly thickened at nodes. Stipules pale green, sometimes tinged pinkish, glabrous or sparsely hairy, hairs red, broadly lanceolate or ovate, 9–25 × 6–15 mm, margin entire, apex acute, persistent. Leaves alternate, distant, oblique, held horizontally; petioles stout, reddish when young, pale green when mature, glabrous or densely hispid, hairs red or pale green, sometimes glabrescent, 6–23 cm long, terete; lamina plain green above, glabrous above, pale green beneath, juvenile leaf reddish, in life succulent, sometimes slightly bullate, glossy, beneath with scattered bristles between veins and on the veins, hairs red, rarely glabrous, asymmetrical, ovate to oblanceolate, 8–16 × 7–17.5 cm, broad side 4.5–10.5 cm wide, base deeply cordate and overlapping, basal lobes 2.5–7.5 cm long, margin ciliate, apex acuminate, acumen 0.5–1.5 cm long; venation palmate-pinnate, 8–10 veins radiating from the base, branching 2–5 times towards margin, veins concolourous, prominent both sides. Inflorescences protogynous in upper leaf axils, simple cyme; slender, 4–6 cm long, peduncle 2–3.5 cm long; bracts several crowded at base, pale green or reddish, ovate, 3–5 × 2–3 mm, margin entire, glabrous, apex acute, persistent; bracteoles similar to bracts but smaller, ovate, 3–4 × 1.5–2 mm, glabrous, margin entire, persistent; female inflorescence to 2.5 cm long; bracts pale green or reddish, ovate, 2–4 × 2–3 mm, margin entire, apex acute, persistent; bracteoles reddish, ovate, 1–2 × 1 mm, margin entire, apex acute, persistent. Male flowers: pedicel reddish, 12–20 mm long; tepals 4, glabrous, outer two tepals reddish outside, pale orange red inside, obovate, 9–12 × 7–8 mm, margin entire, apex acute to rounded, inner two tepals peachy orange or pale orange, lanceolate to narrowly obovate, 11–13 × 3–5 mm; stamens 29–36, cluster globose, sessile; filaments pale yellow, 2–2.5 mm long; anthers lemon yellow, obovate, 1.2–1.5 × 0.5 mm, apex emarginate. Female flowers: pedicel reddish, 5–7 mm long; ovary deep red, ovate, ovary including the wings c.8–9 × 11 mm, wings 3, equal, locules 3, placentas 2 per locule; tepals 5, reddish to orangey, glabrous, outer four tepals broadly elliptic, 8–9 × 4–5 mm, margin entire, apex broadly acute or rounded, inner tepal 7–9 × 3–4; styles 3, lemon yellow, c. 3 mm long, divided to base, broadly anchor-shaped; stigma yellow-orange, papillose forming a continuous twisted band. Capsules reddish, 9–13 × 12–16 mm, glabrous, locules 3, wings 3, equal, broadly rounded or truncate proximally and distally, 2–4 mm wide, thinly fibrous, dehiscing between locule and wing; pedicel strongly recurved, 2.5–6 mm long.

Distribution. Malaysia ( Sarawak). To date, known only from Belaga District (see Figure 1 ).

Habitat. On sandstone boulders or disturbed seasonal creeks in mixed dipterocarp forest at 870–933 m elevation.

Etymology. Named after the type locality at Sungai Kebuho.

Additional specimens examined. MALAYSIA. Sarawak: Belaga District – Linau Forest Management Unit, Coupe 2 A, tributary of Sungai Kajang , 2 ° 16′59′′N, 114 ° 55′17′′E, 24 ix 2016, Ling et al. SFC 7022 ( KEP, SAR) ; Danum Forest Management Unit, Long Tanyit , 2 ° 21′59′′N, 114 ° 33′35′′E, 19 iv 2017, Ling et al. SFC 8288 ( KEP, SAR), 21 iv 2017, Ling et al. SFC 8293 ( KEP, SAR) .

Plants in the population growing in a seasonal creek were more robust, having much larger leaves with petioles to 16 cm long and laminas to 16.5 × 15 cm and the petioles much more densely hairy compared with plants growing on sandstone boulders, whose largest leaves had petioles to 14 cm long that were sometimes glabrous and had laminas to 11 × 9 cm.

Figures

Figure 1. Distribution of Begonia papyraptera and the 12 new species of Begonia recorded from Sarawak and described in this article.

Figure 7. Begonia kebuhoensis S.Julia & C.Y.Ling, sp. nov. A and B, Habit; C, stipule and stem; D, inflorescence; E, male flower; F and G, female flower; H, capsules; I, cross-section of capsule. All photographs taken by C. Y. Ling: A and D, Ling et al. SFC 8293; B, E–G and I, Ling et al. SFC 7012 (the type specimen); C, Ling et al. SFC 8288; H, Ling et al. SFC 7022.