Begonia benaratensis 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 : 6-8

2. Begonia benaratensis S.Julia , spec. nov. ( Figure 4 )

Sect. Petermannia

It is most similar to Begonia apiensis Kiew & S.Julia in its small, glabrous leaves with the lamina as broad as long, in its two main veins with a further two in the basal lobe, in its petiole more-or-less the length of lamina, and the entire margin but B. benaratensis is different from B. apiensis in its creeping habit, larger stipules ca. 5 × 3 mm (not ca. 3 × 2.5 mm), ovate or rounded lamina (not reniform), bigger bracts ca. 5 × 3 mm (not ca. 4 × 2 mm), much larger tepals in female flower 8–10 × 3–8 mm (not 2–2.5 × 1–1.5 mm), larger male flowers ca. 8 × 8 mm (not 4.5–5.5 × 4 mm), number of stamens 25–30 (not 15–20) and narrower fruits ca. 12 × 5 mm (not 10–18 × 6–19 mm).

Type: — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park, Gunung Benarat , 15 April 2012, Julia et al. SFC 2804 (holotype SAR!; isotypes E!, K!, KEP!, L!, SING!, SAR!) .

Creeping herb, rooting at nodes, sometimes branched. Whole plant glabrous. Stems red, ca. 2 mm diameter; internodes 2.5–5(–6.5) cm long. Stipules triangular, ca. 5 × 3 mm, margin entire, apex pointed, persistent. Leaves alternate, distant, straight or sometime pendent. Petioles: 2.5–5 cm, terete. Lamina matt plain green above, paler beneath, in life stiff and fleshy, oblique, reniform, (2–)3.5–4 × (3–) 3.5–5 cm, asymmetric, broad side (1.7–) 2.5–3 cm, base cordate but not overlapping, basal lobes 0.7–1 cm, margin slightly red, with very distant teeth at vein endings, apex acute; main veins palmate, 2 pairs with an additional 2 veins in basal lobe, branching about halfway to margin, slightly prominent on both surfaces. Inflorescences axillary from the upper leaf axils, red, erect, racemose, protogynous, 4–15 cm long with a single female flower below and many male flowers above. Bracts ovate, ca. 8 × 5 mm, margin entire, apex pointed, caducous. Uppermost bracts ovate, ca. 5 × 3 mm, margin entire, apex pointed, caducous. Male flower: pedicel red, 5–15 mm; tepals 2, white, glistening, rounded, ca. 8 × 8 mm, margin entire, apex rounded; stamens 25–30, cluster globose, stalked to 1 mm long; filament to 1 mm long; anthers yellow, oblong or obovate, 0.8–1 × 0.5 mm, apex emarginate. Female flower: pedicel ca. 5 mm long, red; ovary ca. 9 × 9 mm, wings 3, equal, locules 3, placental branches 2 per locule; tepals 5, pinkish, elliptic, 8–10 × 3–8 mm, margin entire, apex rounded; styles 3, ca. 2 mm length, bifurcating; stigma yellow, papillose forming a continuous twisted band. Fruits pendent; pedicel ca. 15 mm long, recurved; capsule reddish, elliptic, 9–14 × 7–11 mm, glabrous, locules 3, wings equal, slightly pointed distally, 2–3 mm wide, dehiscing between the wings and locules. Seeds: barrel-shaped, ca. 0.5 × 0.2 mm, collar cells half the seed length.

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

Habitat: —Slightly damp and lightly shaded vertical cliff faces, sometime on mossy surfaces at 128–300 m elevation.

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

Additional specimen examined (paratype): — MALAYSIA. Borneo. Sarawak. Marudi District: Gunung Mulu National Park – Gunung Benarat, Baei et al. SFC 2835 ( K, SAN, SAR) .

Notes: —The species is most similar to B. apiensis but the habitat is completely different. It grows on lightly shaded mossy rock faces below 300 m compared with B. apiensis that is only found above 800 m. Found in localized patches, B. benaratensis sometimes grows together with B. rhodoneura that is more widespread.

Figures

FIGURE 4. Begonia benaratensis. A. habit; B. protogynous inflorescence with a single open female flower and many young male flowers; C. male flowers; D. fruit. All photos from SFC 2804 by Julia Sang.