Begonia lucychongiana S.Julia & Kiew, 2013

Sang, Julia, Kiew, Ruth & Geri, Connie, 2013, Revision of Begonia (Begoniaceae) from the Melinau Limestone in Gunung Mulu National Park and Gunung Buda National Park, Sarawak, Borneo, including thirteen new species, Phytotaxa 99 (1), pp. 1-34 : 14-16

6. Begonia lucychongiana S.Julia & Kiew , spec. nov. ( Figure 8 )

Sect: Petermannia

In its small size and creeping habit, non-peltate leaves and long inflorescences from the upper leaf axils, it resembles Begonia kasutensis K.G.Pearce from Niah National Park, but from which it can be distinguished by the following characters: longer petiole of the lower leaves 4–8 cm long (not 3.8 cm), the very oblique and much broader lamina 5–10 5–13 cm (not scarcely oblique lamina 4.7–6.2 × 3.9–5.5 cm), the shorter capsule 8–15 × 10–12 mm (not 16 × 12 mm) and stamens numbering 30–46 (not 20).

Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park, Gunung Benarat , 19 April 2012, Sirukit et al. SFC 2839 (holotype SAR!, isotypes K!, KEP!) .

Creeping or scrambling herb with slender runners rooting at the nodes. Whole plant glabrous. Stems rarely branching, dark brown or reddish, to 80 cm long, 2–3(–4) mm diameter, internodes 1.7–6 cm long. Stipule pairs pale green or brownish, broadly lanceolate, 7–15 4–7 mm, entire, apex setose, persistent. Leaves alternate, distant. Petioles reddish brown, lower petioles 4–18 cm long, upper ones 3.5–6 cm long, grooved above. Laminas plain dull dark green or yellowish green, paler or often red beneath, margin sometimes crimson, young leaves reddish above subsucculent when fresh, stiffly papery when dried, very oblique, broadly oval, 5–10 × 5–13 cm, asymmetrical, broad side 3–8.5 cm wide, base deeply cordate, not overlapping, basal lobes 0.7–1.5 cm, margin finely serrate at vein endings with a mucronate tip, apex acuminate. Venation palmate, main veins reddish at base, branching halfway to margin, 2 pairs of veins with 1 in basal lobe, plane above, prominent beneath. Inflorescences axillary from the upper leaf axils, reddish brown or purplish, erect and longer than the petioles, racemose, unbranched, protogynous, 5–16.5 cm, with a single or a pair of female flowers below, many male flowers above. Peduncle (1.5–) 7.5–9.5 cm. Bracts of female flowers setose like the stipules, 7–12 × 4–10 mm, caducous; uppermost bracts of male flowers small, pale green or brownish green, elliptic, 3–12 mm × 2–8 mm, margin entire, persistent. Male flower: pedicel pinkish or rosy red, 2–5 mm long; tepals 2, white or creamy yellow, rotund, 2–9 × 1.5–8 mm, with short hairs outside, margin entire, apex rounded; stamens 30–46, cluster globose, 1.7–4 mm wide, stalked 3 mm long; filament 0.5–1.2 mm, anthers pale yellow, obovate, 0.5–0.6 × 0.2 mm, apex emarginate. Female flower: pedicel reddish, with short hairs, 5– 10 mm long; ovary green tinged reddish, ovoid, 7–12 × 4–10 mm, wings 3, 1.5–2 mm wide, unequal, locules 3, placental branches 2 per locule; tepals 5, isomorphic, cream-coloured or slightly pink, broadly obovate, 6– 11 × 4–8 mm, margin entire, apex rounded; styles 3, pale green or lemon yellow, 2 mm long, free to base and bifurcating with the ultimate branches broadly U-shaped and curled at the tips; stigma pale yellow, papillose, forming a continuous twisted band. Fruits pendent; pedicel 7–13 mm, stiff and recurved, capsule broadly ovate, proximally slightly narrowed, distally rounded, with short sparse hairs, 8–15 × 9–13 mm, wings unequal, larger wing 2.5–5 mm wide and smaller wings 1.5 mm wide, locules 3, stiffly papery, splitting between the locules and wing. Seeds barrel-shaped, 0.2–0.5 × 0.1–0.2 mm, collar cells more than half the length of the seed.

Distribution: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park. Endemic in Melinau limestone where it is found in Gunung Benarat, Bukit Agung, Hidden Valley, Gunung Api, Clearwater Cave and the limestone hill near the airport.

Habitat: —Creeping on shady limestone rocks or on steep vertical cliffs up to 900 m.

Etymology: —This species is named in honour of Ms Lucy Chong, Forest Pathologist (1982–2011) and currently the Deputy General Manager of Sarawak Forestry Corporation who has strongly supported begonia research and study of the limestone flora in Sarawak.

Additional specimens examined (paratypes): — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park – Melinau Gorge, Julaihi S 86850 ( KEP, SAR); Burtt & Wood B 2315 ( E, SAR); Gunung Api, Anderson S 31754 ( K, L, SAR); Near Camp 5, Julaihi et al. S 84401 ( SAR); North side of Melinau Gorge, Nielsen 397 ( AAU, SAR); Sungai Melinau, Wind Cave , Stone 13600 ( SAR), Sirukit & Mohd. Azam SFC 3004 ( E, KEP, SAR); Gunung Benarat, Chai S 30411 ( K, L, SAN, SAR, SING), Abang Mohtar & Othman S 49665 ( K, KEP, L, SAR); Hidden Valley Yii & Talib S 58702 ( KEP, L, SAR); Boardwalk to Clearwater Cave , Julia et al. S 99217 ( E, SAR); Clearwater Cave , Julia et al. S 99216 ( E, KEP, SAR); Trail from Lobang Cina to Camp 5, Sirukit & Mohd. Azam SFC 3002 ( K, KEP, L, SAR) .

Notes: —This species is common and widespread, creeping on rock faces in lowland limestone forest.

6a. Natural hybrid between Begonia conipila and B. lucychongiana ( Figure 9 )

One plant, SFC 2836, was found on Gunung Benarat growing close by to Begonia conipila but differing from it in being glabrous, in the leaf margin being finely serrate (that of B. conipila is doubly serrate) and the male flowers being deep red at the base. In spite of an intensive search no other individual resembling it was found. Begonia conipila is one of the commonest and most widespread begonia species on the Melinau limestone where it grows on rocks from the base to almost the top of the limestone massifs. It is characterized not only by its coloration ( Figure 3 ), it is the only variegated species here, but also by its indumentums of long, white hairs each on a raised conical base. Although it shows variation in its variegation, plants of B. conipila are always densely hairy. The fact that only one individual was found suggests that SFC 2836 does not represent a new species but rather that it might be a natural hybrid. The pattern and coloration of leaves of SFC 2836 clearly suggests B. conipila as one of the possible parents. The only other limestone species that creeps on rock face, roots from the nodes and has medium-sized leaves that are slightly longer than wide is B. lucychongiana . Its leaves are always glabrous, are often pale green underneath but the upper surface is dull dark green or yellowish green and is never variegated. Both occupy the same habitat on the same cliff face although B. lucychongiana only grows to 900 m elevation. In its glabrous and minutely toothed leaf, it resembles SFC 2836, suggesting that SFC 2836 may be a hybrid between it and B. conipila . However, SFC 2836 is different from both these species in the deep red base of the male tepals contrasting with those of B. conipila (white or light green) and B. lucychongiana (white or creamy yellow), stamens 15–18 in SFC 2836 compared to 10–11 in B. conipila and 30–46 in B. lucychongiana . Further investigation is required to confirm this hybrid status.

Figures

FIGURE 3. Begonia apiensis. A. habit with protogynous inflorescence; B. inflorescence with a single female flower and several immature male flowers; C. male flowers; D. fruit. All photos from SFC 3006 by Connie Geri.

FIGURE 8. Begonia lucychongiana. A. habit with creeping stem; B. inflorescence with female flower and young buds of male flowers; C. close-up of female flower; D. close up of open male flower; E. fruit. Photos A & B from SFC 3002 by Julia Sang; photos C–E from SFC 3004 by Connie Geri.

FIGURE 9. B. conipila × B. lucychongiana. A. habit with glabrescent plants; B. inflorescence with old fruit and male flowers. Photos from SFC 2836 by Connie Geri.