Begonia lansatensis Kiew & 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 : 67

9. Begonia lansatensis Kiew & S.Julia , spec. nov. ( Figure 6 )

Similar to Begonia tebiang S. Julia & Kiew (2016: 28) in its creeping habit and ovate leaves but it is different in its terete petiole (vs. grooved), palmate venation (vs. palmate-pinnate venation), its male flower with longer pedicel, 7–8 mm long (vs. 2–5 mm long) and larger outer tepals, 11–13 × 7–7.5 mm (vs. 6–8 × 4–6 mm) and female flowers with a smaller ovary 4–6 mm (vs. 14–15 mm). Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP, Sungai Lansat, 23 April 2016, Julia et al. SFC 6806 (holotype SAR!).

Creeping herb, rooting at the nodes. Stem to 30 cm long, 4–5 mm thick, erect apex 3.5–4.5 cm long, green or greenish brown, brown pubescent; internodes 2.3–4.7 cm long. Stipule broadly ovate, pale green, hispid, hairs white, apex acuminate, 11–17 × 7–12 mm, acumen to 2 mm long, tipped by a hair, slightly keeled at the tip, margin ciliate. Upper petioles 2–3 cm long, lower petioles 4–6 cm long, pale green, succulent, terete, brown pubescent. Lamina broadly ovate, 7.5–9.5 × 7–9.5 cm, broad side 4.5–6.25 cm, basal lobe 1 cm long, base cordate, almost equal, sometimes overlapping, margin dentate, teeth tipped by a hair, apex shortly acuminate, ca. 3 mm long, plain green or with white spots between the veins often coalescing into lines, also with spots aligned along the margin, sparsely hispid above, scattered on the upper surface, glabrous beneath, veins brown pubescent beneath; venation impressed above, prominent below, palmate, 2 pairs from the base bifurcating towards the margin, 2 pairs on either side of the midrib, 1 pair in each of the basal lobes, main veins red at the base. Inflorescence protogynous, from the uppermost leaf axil, racemose, red, 4.5–7.5 cm long, peduncle 2–4.5 cm long. Bract similar to stipule, ovate, 9–11 × 8–11 mm; bracteoles up to 6 pairs, lower pair of bracteole ovate, 7–8 × 4–5 mm, upper pairs ca. 6.5 × 6 mm, whitish green. Male flower: pedicel white, 7–8 mm long; tepals 4, glabrous, white, outer tepals 11–13 × 7–7.5 mm, inner tepals 7–8 × 3 mm, stamens 34–38, ca. 2 mm long, cluster conical, subsessile; filament 0.5–1 mm long, pale yellow, anther lemon yellow, obovate, ca. 1 × 0.5 mm, apex emarginate. Female flower: pedicel 1–3 mm long; ovary white tinged pink or pale green, ovate, 3–6 × 4–10.5 mm, wings 3, unequal, locules 3, placentas 2 per locule; tepals 5, outer 4 tepals 7–8 × 5–7 mm, inner tepal 5–6 × 3–4.5 mm, styles 3, ca. 2 mm long; stigma yellow, anchor-shaped. Capsule not seen.

Distribution: — MALAYSIA. Borneo. Sarawak. Endemic in Gunung Mulu NP; to date recorded only from Sungai Lansat.

Habitat: —In mixed dipterocarp forest, usually growing on very steep slopes with a thick leaf litter layer near seasonal streams and above river at elevations below 400 m.

Etymology: —Named after the type locality, Sungai Lansat, from where it was first collected.

Additional specimen examined: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu NP – Eastern bank of Tapin, Jermy 13868 (K).

Notes: —Two different forms were observed, i.e., individuals with plain green leaves and individuals with white spotted leaves. Both forms were found growing in the same population.

Figures

FIGURE 6. Begonia lansatensis Kiew & S.Julia. A. Habit showing individuals with plain green leaves; B. Individual with white spotted leaves; C. Stipule; D. Inflorescence showing female flower; E. Male flower; F & G. Female flower; H. Transverse section of female flower. Photos A–G by S. Julia and Photo H by C.Y. Ling (all photos from SFC 6806).