Begonia minutitepala S. Julia & Kiew, 2018

Yiing, Ling Chea, Sang, Julia & Kiew, Ruth, 2018, Begonia species (Begoniaceae) from Gunung Penrissen, Sarawak, Borneo, including two new species and a new subspecies, Phytotaxa 381 (1), pp. 12-21 : 15-17

4. Begonia minutitepala S. Julia & Kiew , sp. nov. ( Figure 2 )

Sect. Petermannia

Similar to Begonia densiretis Irmsch (1953: 490) in its habit but it is differentiated by its more robust habit with stems to 100 cm tall and 4–8 mm thick (vs. stems ca. 35 cm tall and 2–4.5 mm thick); larger stipules at 6–9 mm wide (vs. 3–4 mm wide); larger leaves at 14.5–19 × 8–10.5 cm (vs. 9.5–14 × 5.5–8 cm); smaller basal lobes at 0.6–1 cm (vs. basal lobe well developed, 1.5–2.5 cm), larger ovary at 11–15 × 13–17 mm (vs. 8.5 × 4.5 mm), longer fruits at 13–17 × 15–20 mm with wing tips distally pointed (vs. 10–12.5 × 4.2–5 mm and wing tips rounded). Type: — MALAYSIA. Borneo, Sarawak, Padawan District : Gunung Penrissen , 3 December 2017, Julia et al. SFC 5586 (holotype SAR!; isotype KEP!) .

Cane-like begonia to 50–100 cm tall, much-branched. Stems reddish brown or dull green, minutely pubescent, terete, 5–8 mm thick, internodes 5–9.5 cm long, swollen at the nodes. Stipules lanceolate, 12–23 × 6–9 mm, strongly keeled, margin entire, apex attenuate or setose, seta to 2 mm long, pubescent, caducous. Leaves alternate, oblique, held horizontally or sometimes slightly vertically; petioles greenish brown, 1.6–3 cm long, grooved above, minutely pubescent; lamina plain green above, paler beneath, above glabrous or sparsely sprinkled with bristles between the veins, hairs blackish or brownish each on a raised base, beneath glabrous, in life succulent, glossy, broadly ovate, 14.5–19 × 8–10.5 cm, broad side 5–7 cm wide, base shallowly cordate, basal lobes 0.6–1 cm, margin minutely serrate, apex acuminate, 1.5–2.3 cm long; venation pinnate, veins sunken above, prominent below, 4–5 veins on either side of the midrib, branching 2 or 3 times, in life veins pale green on both surfaces, reddish brown towards the base, 2–3 veins in the basal lobe, tertiary veins reticulate, prominent above, slightly so below. Inflorescences protogynous, in the upper leaf axils, racemose with 2– 3 female flowers at the base and many male flowers above, rachis shortly branched, 8–20 cm long, peduncle pale green, pubescent, 2.5–4.5 cm long. Bracts greenish, lanceolate, 12–15 × 4–7 mm, margin entire, apex acute, caducous; bracteoles lanceolate, 5–11 × 3–4 mm, caducous. Male flowers: pedicel greenish yellow, 4–5 mm long, sparsely pubescent; tepals 2, greenish to yellowish green, slightly reflexed, oval, 3–4 × 4 mm, margin entire, apex rounded; stamens 20–26, cluster conical, torus ca. 1 mm long; filaments pale yellow, ca. 1 mm long; anthers pale yellow, oblong, ca. 1 × 0.6 mm, apex emarginate. Female flowers: pedicel pale green, 7–15 mm long, minutely pubescent; ovary pale green or yellowish green, wings pale green, wing with acute tip, 11–15 × 13–17 mm, wings 3, slightly unequal, locules 3, placentas 2 per locule; tepals 5, mostly free, rarely joined in the lower quarter of the tepal, yellowish with greenish margin, outer 4 tepals ovate, 10–15 × 5–10 mm, inner tepal 8–12 × 5–7 mm, margin minutely toothed or entire, apex acute; styles 3, yellowish, ca. 2 mm long, divided to base, deeply Y-shaped; stigma yellowish brown, papillose forming a continuous twisted band. Fruits 2–3 along the rachis, green, sparsely pubescent, 13–17 mm long, 15–20 mm wide, locules 3, wings 3, 5–7 mm wide, glabrous, slightly unequal, acute proximally, truncate distally or tip acute, thinly fibrous, dehiscing between locule and wing; pedicel pendent, 8–12 mm long, pubescent, greenish.

Distribution: —Endemic in Borneo. So far known only from Gunung Penrissen, Padawan District, Sarawak.

Habitat: —In hill forest at elevations to 1000 m. In semi-shaded areas it grows together with Begonia dasycaulis on rocky slopes with a thin layer of leaf litter or sometimes on mossy rocky slopes

Etymology: —Latin, minutus = very small; referring to the very small tepals.

Notes: —The species is somewhat similar to B. lailana in its cane-like habit but it is distinct in having longer petioles, racemose inflorescences, larger bracts, shorter tepals of male flower, fewer stamens, and a shorter fruit with a shorter pedicel.

5. Begonia natunaensis C.W.Lin & C.-I. Peng. Taiwania 59(4) (2014) 368. Type : — INDONESIA. Natuna Island, Mt. Ranai, 11 December 2014, C.W. Lin 563 (from cultivated plants: holotype BO n.v.; isotypes HAST n.v., TAIF n.v.). Sect. Jackia

Figures

FIGURE 2. Begonia minutitepala A. Habit; B. Stipule; C. Close-up of upper surface of leaf; D. Inflorescence; E. Male flower; F & G. Female flower; H. Fruit; I. Cross-section of capsule. All photos from SFC 5586 by Ling Chea Yiing.