Begonia jokwaniana C.Y.Ling & S.Julia, 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 : 65-67

8. Begonia jokwaniana C.Y.Ling & S.Julia , spec. nov. ( Figure 5 )

In its habit and broadly ovate leaves, it is similar to Begonia propinqua Ridley (1906: 249) but it is different in its smaller, ovate stipules 12–15 × 8–11 mm (vs. broadly lanceolate stipule, 18–30 × 6–8 mm), more numerous veins, 5–8 veins on either side of the midrib and 2–3 veins in the basal lobes (vs. 3–5 veins on either side of the midrib and 4–5 veins in the basal lobes), longer peduncle, 3.5–4 cm long (vs. peduncle 4.5–7 cm long), wider bracts ca. 12 mm wide (vs. ca. 6 mm wide), male flower with longer pedicels 9–11 mm long (vs. 4–8 mm long), female flowers with larger ovate tepals 12–13 × 9–10 mm (vs. elliptic, 10–12 × 5 mm), fruits single (vs. in pairs) and capsules shorter and broader 6–7 × 10–11 mm (vs. ca. 9 × 6 mm). Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP, Camp 4, 18 April 2016, Ling et al. SFC 6914 (holotype SAR!).

Cane-like begonia to 1.5 m tall. Stem red brown, succulent, 4–6 mm thick, pubescent, little-branched; internodes 3.5–7.5 cm long, slightly thicker at nodes. Stipule pale green, ovate, 12–15 × 8–11 mm, slightly keeled, margin entire, apex setose, seta to 2 mm long, caducous. Leaves alternate, distant, held horizontally. Petiole red-brown, (2.5–) 6–12.5 cm long, grooved above. Lamina ovate, oblique, plain green above, pale green beneath, sparsely bristly above, hairs pale green on a raised base, glossy and fleshy in life, 11–16.5 × 8–13 cm, broad side 6–9.5 cm, base cordate, sometimes overlapping, basal lobes 3–5 cm wide, margin irregularly dentate; venation palmate-pinnate, reddish near the base above, otherwise pale green, 5–8 veins on either side of midrib, 2–3 veins in the basal lobes, prominent on both surfaces. Inflorescence protogynous, in the upper leaf axil, paniculate, 12–33 cm long, erect, peduncle 3.5–4 cm long, reddish, pubescent, 1– 3 female flowers at the base, above many male flowers; bracts pale green, ca. 10 × 12 mm, apex acute, glabrous, margin entire, caducous; bracteoles up to 4 pairs, ovate, 8–10 × 10–13 mm, pale green, margin entire, apex acute to rounded, caducous. Male flower: pedicel white, 9–11 mm long, glabrous, tepals 4, outer 2 tepals white inside, pale green outside, broadly elliptic, 7–8 × 4–6 mm, margin entire, apex broadly acute to rounded; inner 2 tepals white or whitish green, lanceolate, 5–6 × 1.5–2 mm, margin entire, apex bluntly acute; stamens 16–20, pale yellow, cluster globose, subsessile; filaments pale yellow, ca. 0.5 mm long; anthers yellow, oblanceolate, ca. 1.5 × 0.8–1 mm, apex emarginate. Female flower: pedicel pale green, ca. 9 mm long, glabrous; ovary broadly obovate, ca. 10 × 15 mm, pale green-white, wings 3, equal, locules 3, placentas 2 per locule; tepals 5, whitish to white with a hint of pale green, ovate, 12–13 × 9–10 mm, margin entire, apex rounded; styles 3, yellowish green, ca. 2 mm long, divided to base, shallowly Y-shaped above; stigma pale yellow, papillose forming a continuous twisted band. Fruit 12–14 mm long, 17 mm wide across the wings, glabrous, locules 3, wings 3, dull green, equal, 4–5 mm wide, thinly fibrous, rounded proximately, rounded to slightly truncate distally; pedicel pendent, 12–15 mm long.

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

Habitat: —Mossy upper montane forest at ca. 1592 m elevation.

Etymology: —Named after Jok Wan, currently Park Ranger at Gunung Mulu NP, who facilitated the Begonia survey at Gunung Mulu NP.

Additional specimens examined: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP – Ulu Sg. Melinau Paku, Anderson S 4049 (SAR); Melinau Gorge, Abang Mohtar S 49525 (SAR).

Notes: —The species is similar to B. melinauensis in its broadly ovate leaves but is different in its glossy lamina (in life) that is sparsely bristly above, its male flowers with 2 tepals and its shorter capsule.

Figures

FIGURE 5. Begonia jokwaniana C.Y.Ling & S.Julia. A. Habit; B. Stipule; C. Upper surface of leaf; D. Male inflorescence; E & F. Male flower; G. Female flower; H. Fruit; I. Transverse section of fruit. All photos from SFC 6914 by C.Y. Ling.