Begonia apiensis Kiew & 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 : 5

1. Begonia apiensis Kiew & S.Julia , spec. nov. ( Figure 3 )

Sect. Petermannia

It is most similar to Begonia kasutensis K.G. Pearce (2003: 82) from Niah National Park, Sarawak in its glabrous leaves with laminas as broad as long with two main veins and an additional two veins in the basal lobe; however, B. apiensis is different in its petioles that are more-or-less the length of lamina, its plain green and smaller lamina 2.2– 3.5 × 2.2–4 cm with an almost entire margin, whereas B. kasutensis has a petiole less than half the length of lamina, the lamina is variegated and is larger, 4.7–6.2 × 3.9–5.5 cm, and the margin is irregularly serrulate.

Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park, Gunung Api , 17 April 2012, Sirukit & Mohd. Azam SFC 3006 (holotype SAR!; isotypes E!, K!, KEP!, L!, SAN!) .

Semi-erect to 35 cm tall or sometimes creeping herb, rooting at nodes, often branched. Whole plant glabrous. Stems red, to 35 cm long, 1–3 mm diameter; internodes 1–7.5 cm long. Stipules ovate, ca. 3 × 2.5 mm, margin entire, apex acute, caducous. Leaves alternate, distant, straight or sometimes pendent. Petioles 2.5–3(–5.5) cm long, terete. Laminas matt plain green above, glaucous beneath, stiffly papery when dried, oblique, ovate, 2.2– 3.5 × 2.2–4 cm, asymmetric, reniform, broad side 1.5–2.2 cm, base cordate but not overlapping, basal lobes 0.7–1.5 cm, margin sometimes red, almost entire with very small teeth at the vein endings, apex rounded to bluntly acute; main veins palmate, 2 pairs with an additional 2 veins in basal lobe, branching about halfway to margin, slightly prominent or flat above, prominent beneath. Inflorescences axillary from the upper leaf axils, pink or red, erect and longer than petioles, racemose, protogynous, 5–17 cm long with a single female flower below and up to 3 few-flowered branches to 1.5 cm long with male flowers above. Bracts elliptic, ca. 4 × 2 mm, margin entire, caducous. Uppermost bracts rounded, ca. 2 × 2 mm, margin entire, caducous. Male flower: pedicel red, 5–11 mm; tepals 2, white or pale pink, glistening, circular or broadly oval, 4.5–5.5 × 4 mm, margin entire, apex rounded; stamens 15–20, cluster globose, stalked 2 mm long; filament 1–1.5 mm; anthers yellow, oblong, 1–1.5 × 0.5 mm, apex emarginate. Female flower: pedicel to 6 mm long, red; ovary spindleshaped, ca. 6 × 3 mm, wings 3, unequal, locules 3, placental branches 2 per locule; tepals 5, pink, elliptic, 2– 2.5 × 1–1.5 mm, margin entire, apex broadly acute; styles 3, to 1 mm length, bifurcating; stigma pale yellow, papillose forming a continuous twisted band. Fruits pendent; pedicel 15–25 mm long, stiff and recurved; capsule red, broadly oblong, 10–18 × 6–19 mm, glabrous, locules 3, wings equal, parallel but rounded or truncate distally, rounded or narrowed proximally, 3–5 mm wide, dehiscing between the wings and locules. Seeds: barrel-shaped, ca. 1 × 0.5 mm, collar cells half the seed length.

Distribution: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park, Melinau limestone. Endemic in Gunung Api.

Habitat: —Lower montane forest at 830–1170 m elevation on damp shady mossy vertical cliff faces or on limestone boulders on peat soil.

Etymology: —The species named after Gunung Api, the only known locality for this species.

Additional specimens examined (paratypes): — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park – Gunung Mulu, Burtt B 8246 ( E, SAR); Yii & Abu Talib S 58880 ( KEP, K, SAR); Julaihi S 86812 ( KEP, SAN, SAR) .

Notes: —It is a unique limestone species because it grows at high elevation in lower montane forest above 800 m. It is a decorative species in its tiny rounded leaves and low often creeping habit.

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.