Begonia vulgarioides S.Julia & Kiew, 2018

Sang, Julia, Kiew, Ruth & Yiing, Ling Chea, 2018, The Begonia flora of Gunung Mulu and Gunung Buda National Parks, Sarawak, Borneo, including five new species, Phytotaxa 381 (1), pp. 58-79 : 74

18. Begonia vulgarioides S.Julia & Kiew , spec. nov. ( Figure 9 )

Similar to Begonia vulgare S. Julia & Kiew (2013:26) in its habit but it is different in its generally shorter, little branched stem 45–90 cm tall (vs. to 2 m tall and much branched stem), shorter basal lobe 0.5–1 cm long (vs. 1–1.5 cm long), minutely serrate leaf margin (vs. dentate margin), shorter inflorescences 4–9 cm long with flowers in sessile clusters (vs. many flowered, much branched inflorescences 9–13 cm long), and shorter capsule 17–27 mm long with wings narrowed to base and with distal tip sharply pointed (vs. 34–45 mm long with wings rounded at the base and at the tip). Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP, Main trail from Park Headquarters to Camp 1, Julia et al. SFC 6667 (holotype SAR!).

Cane-like begonia 45–90 cm tall, sparsely branched. Stems reddish brown, minutely pubescent, terete, 5–8 mm thick; internodes 2.5–7.5 cm long, swollen at the nodes. Stipules narrowly lanceolate, 10–24 × 4–8 mm, strongly keeled, margin entire, apex attenuate, pubescent. Leaves alternate, oblique, held horizontally or sometimes slightly vertically; petioles reddish brown, 1–3 cm long, grooved above, minutely pubescent; lamina broadly ovate or obovate, 13– 21 × 6.5–11 cm, broad side 4.3–7 cm, base shallowly cordate, basal lobes 0.5–1 cm long, margin minutely serrate, apex acuminate, acumen 1–2 cm long or almost cuspidate, plain green on both surfaces, paler beneath, sparsely sprinkled with bristles between veins, hairs blackish or brownish on a raised base, glabrous beneath, in life succulent, membranous when dry, glossy; venation pinnate, veins sunken above, prominent below, 4–5 veins on either side of the midrib, in life veins pale green on both surfaces, reddish brown towards the base, 1–2 veins in the basal lobe. Inflorescences protogynous, axillary in the upper leaf axils, racemose, rachis unbranched, 4–9 cm long, peduncle pale green, pubescent, 1.5–4.5 cm long, with 3–4 sessile clusters of up to 9 flowers. Bracts greenish, lanceolate, 10–15 × 4–5 mm, margin entire, apex acute, caducous; bracteoles ovate, 9–13 × 4–6 mm, caducous. Male flowers: pedicel yellowish, 2–10 mm long, sparsely pubescent; tepals 2, pale green, pale reddish brown towards the base, slightly reflexed, oval, 4–6 × 3–5 mm, margin entire, apex rounded; stamens 34–40, cluster conical, subsessile; filaments yellowish brown, 0.5–1 mm long; anthers yellowish brown, obovate, 1–1.5 × 1 mm, apex emarginate. Female flowers: pedicel yellowish green or pale green, 7–8 mm long, minutely pubescent; ovary yellowish green, wings 3, unequal, pale green, bell-shaped with pointed wing tips, 12–27 × 6–13 mm, locules 3, placentas 2 per locule; tepals 5, yellowish with a green margin, outer 3 tepals narrowly ovate, 6–12 × 4–7 mm, inner 2 tepals 7–12 × 3–5 mm, margin toothed on the upper half, apex acute; styles 3, pale yellowish, ca. 2 mm long, divided to base, above deeply Y-shaped; stigma pale yellow with reddish stripe, papillose forming a continuous twisted band. Capsules 2–4 along the rachis, greenish yellow or pale green, sparsely pubescent, 17–27 × 10(–15)– 30 mm, locules 3, wings 3, unequal, narrowed proximally, distally truncate with a sharply pointed tip, 1–4 mm wide, thinly fibrous, dehiscing between locule and wing; pedicel pendent, 6–10 mm long, pubescent, greenish.

Distribution: — MALAYSIA. Borneo. Sarawak. Endemic in Gunung Mulu NP.

Habitat: —A common species in flat alluvial forest above the riverbank and on limestone-derived soil, frequently forming dense populations.

Etymology: —Greek, - oides = resembling; similar to Begonia vulgare .

Additional specimens examined: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP – ascent to Gunung Mulu, Burtt & Woods B 2058 (SAR); entrance to Gua Rusa from Garden of Eden, Carlo Hansen 66 (K).

Notes: — Begonia vulgare and B. vulgarioides sometimes grow sympatrically but they would not be confused because their leaf venation, inflorescence and fruits are distinct (see diagnosis above).

Figures

FIGURE 9. Begonia vulgarioides S.Julia & Kiew. A. Habit; B. Stipule; C. Male inflorescence and fruit; D. Male inflorescence; E. Female flower; F. Fruit; G. Transverse section of fruit. Photos A–F by S. Julia and Photo G by C.Y. Ling (all photos from SFC 6667).