Begonia rhodoneura S.Julia, 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 : 23-24

10. Begonia rhodoneura S.Julia , spec. nov. ( Figure 13 )

Sect. Petermannia

In habit and leaf shape, this species resembles Begonia kachak K.G.Pearce from Niah National Park but it is different in its more or less sessile inflorescence with one female flower in the leaf axil that is distally much branched with many small white male flowers. The male tepals measure 4.5–5 × 5 mm compared with the longer inflorescence of B. kachak that is up to 29 cm long of which the peduncle is 14 cm long. The female flowers are in pairs and the tepals measure 7 × 5.5 mm. In addition, its fruits are much narrower (19–)22(–30) × 10–13(–17) mm compared with ca. 19 × 16 mm for B. kachak .

Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park, Gunung Benarat , 15 April 2012, Julia et al. SFC 2801 (holotype SAR!; isotypes E!, K!, KEP!, L!, SAN!, SAR!, SING!) .

Scrambling horizontally to 1.5 m tall, bushy and branching, sometimes creeping on rock surfaces or tree trunks. Stems reddish brown, slender, woody, minutely ferrugineous, slightly swollen at nodes, reddish, internodes (2–) 2.5–5.5 cm long, 5–9 mm diameter. Stipules brownish red, lanceolate, ca. 14 × 3 mm, margin entire, apex setose, caducous and leaving a circular scar. Leaves alternate, distant or arranged close together. Petioles minutely ferrugineous and dark red, 7–9.5 cm, slender. Laminas dark green, paler beneath, slightly velvety above, fleshy when fresh, papery when dried, very oblique, broadly ovate, 6–14.5 × 6–13.5 cm, asymmetric, broad side 7–9.5 cm, base cordate overlapping, basal lobes rounded, 1.5–2 cm, margin minutely toothed, apex acuminate. Venation palmate, main veins glabrous beneath, 2 pairs at the base, with 2 pairs along the midrib and 2 veins in basal lobe, branching twice before reaching the margin, impressed above, slightly prominent beneath, veins red below, dark red above. Inflorescences axillary, red, erect and shorter than petioles, protogynous, with one female flower directly in the leaf axil with the male flowers above on a panicle with a total length (3.5–)7(–11.5) cm long. Bracts elliptic, pale green, ca. 12 × 5 mm, margin entire, caducous. Uppermost bracts below the male flower greenish, ovate, ca. 10 8 mm, margin entire, caducous. Male flower: pedicel red ca. 7 mm; tepals 2, red at the base becoming white towards the tip, glabrous outside, rounded, 4.5–5 × 5 mm, margin entire, apex rounded; stamens more than 40, cluster globose, stalk 1 mm long; filament ca. 1 mm long, anthers pale yellow, obovate, ca. 1 × 0.5 mm, apex emarginate. Female flower: pedicel 10 mm, pink, with short hairs; ovary greenish, oblong, ca. 12 × 5 mm, minutely ferrugineous, wings 3, equal, locules 3, placental branches 2 per locule; tepals 5, greenish, elliptic, ca. 10 × 7 mm, margin toothed, apex acute; styles ca. 2 mm long, free to base and bifurcating with greenish papillose stigma forming a continuous twisted band. Fruits pendent; pedicel 10–12 mm long, stiff and recurved; capsule oblong, 19–22(– 30) × 10–13(–17) mm, glabrous, locules 3, wing unequal, narrowed proximally, 2–5 mm wide, stiffly papery, dehiscing between the wings and locules. Seeds barrel-shaped, ca. 0.5 mm long, collar cells more than half the seed length.

Distribution: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park and Gunung Buda National Park. Endemic in the Melinau limestone. Widespread from Lobang Cina, Gunung Benarat, Bukit Agung and Gunung Buda.

Habitat: —Common. In lowland limestone forest on limestone boulders or mossy rock faces, at 102–235 m elevation.

Etymology: —It takes its name from its conspicuous fine dark red veins that contrast with the bright green lamina.

Additional specimens examined (paratypes): — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park –Bukit Agung, Julia et al. SFC 2813 ( SAN, SAR, SING), SFC 2822 ( K, SAR); Gunung Benarat , Beai et al. SFC 2833 ( E, K, KEP, SAR), Abang Mohtar et al S 49472 ( K, KEP, L, SAR); Lobang Cina, Abang Mohtar & Othman S 49413 ( SAR), Anderson & Keng S 4452 ( K, SAR) . Gunung Buda National Park – Gunung Buda, Julia et al. SFC 2824 ( KEP, SAR, SING), Burtt B 8342 ( E, SAR) .

Notes: —The most common begonia on limestone outcrops and isolated boulders at Lobang Cina, Gunung Benarat, Gunung Buda and Bukit Agung.

Figures

FIGURE 13. Begonia rhodoneura. A. habit; B. juvenile plant; C. male flowers; D. female flower taken from specimen preserved in spirit; E. fruit taken from specimen preserved in spirit. Photos from SFC 2801 by Julia Sang.