Begonia papulifolia S.Julia & C.Y.Ling, 2016

Sang, Julia, Kiew, Ruth & Yiing, Ling Chea, 2016, Six new species of Begonia (Begoniaceae) from Central Sarawak, Borneo, Phytotaxa 277 (2), pp. 171-181 : 175-176

3. Begonia papulifolia S.Julia & C.Y.Ling , spec. nov. ( Figure 4 )

Section Petermannia

Diagnosis: —Similar to Begonia lailana Kiew & Geri (2003: 117) is its cane-like habit, short petiole and lamina shape and size, in its 2 tepals in the male flower and inflorescence type but it differs in the stems, petiole and upper leaf surface being hispid (vs. glabrous in B. lailana ), in its smaller stipules 12–15 × 4 mm (vs. 15–27 × 6–10 mm), narrower male tepals 5–7 × 3–4 mm (vs. 6–7 × 6–7 mm) and smaller oblong capsule 10–14 × 9–13 mm (vs. triangular in outline and 20–27 × 18–28 mm). In addition, its leaves are always green beneath (vs. leaves B. lailana are sometimes deep maroon beneath).

Type: — MALAYSIA. Borneo. Sarawak. Kapit District: Bukit Ngingit, Sungai Sedik, 6 August 2015, Ling et al. SFC 5702 (holotype SAR!, isotype KEP!, SNP!).

Cane-like herb to 50 cm tall. Indumentum on stem, petiole, upper leaf surface and lower surface of veins hispid, hairs white, to 3 mm long. Stems reddish to green-brown, 2.5–4 mm thick, internodes (2.5–) 4–7 cm long, branched, thicker at nodes. Stipules pale green, lanceolate, 12–15 × 4 mm, margin entire, keeled, apex acuminate, acumen 1–2 mm long, caducous. Leaves alternate, distant, oblique, held more or less horizontally; petioles reddish brown to greenish, ca. 0.5 cm or 2–3 cm long, slightly grooved above; lamina plain green above, paler beneath, sometimes tinged pink especially near margin, densely pilose hairs white with slightly raised bases giving pimply appearance above, glabrous except on midrib and veins white pilose below, in life succulent, matt, drying tissue-paper thin, asymmetric, oblanceolate or narrowly ovate, 9–17 × 5–8.5 cm, broad side 3–6 cm wide, base unequal, narrow side concave, broad side rounded, basal lobes ca. 0.5 cm long, margin toothed, scalloped in larger leaves, apex acuminate, acumen 1.2–2 cm long; venation pinnate, veins greenish above, pale green beneath, 5–6 veins on either side of the midrib, prominent at both sides. Inflorescences protogynous, terminal or axillary in the upper leaf axils, 6.5–9.5 cm long, peduncle 2–2.5 cm, female flower below, single or rarely 2, paniculate, upper part with short lateral branches to 7 mm long with cymules of male flowers. Bracts pale green, lanceolate, 10–12 × 3–4 mm, margin entire, keeled, caducous; bracteoles similar to bracts but smaller, 4–6 × 2–4 mm, caducous. Male flowers: pedicel pinkish, 2–4 mm long; tepals 2, white, sometimes tinged pink towards base, oval, 5–7 × 3–4 mm, margin entire, apex rounded; stamens 23–25, subsessile; filaments yellow, ca. 0.5 mm long; anthers pale yellow, obovate, ca. 0.5 × 0.3 mm, apex emarginate. Female flowers not seen. Capsules pale green sometimes wings tinged pink, shortly oblong in outline, 10–14 × 9–13 mm, glabrous, locules 3, placenta 2 per locule, wings 3, equal, truncate or broadly rounded proximally and distally, 3–4 mm wide, thinly fibrous, dehiscing between locule and wing; pendent on pedicel 7–10 mm long, pale green.

Etymology: —Latin, papula = pimple; folia = leaf; referring to the leaf surface where the hairs on the upper surface are raised on pointed pimples.

Distribution: — MALAYSIA. Borneo. Endemic in Sarawak. So far known only from type locality.

Habitat: —Sandstone hill, along stream with mudstone boulders at 592 m elevation, lithophyte growing on soil and rocks in shade.

Proposed conservation status: —Critically Endangered. The species is known only from a single locality that lies outside the network of Totally Protected Areas. The habitat is threatened by disturbance due to logging.

Figures

FIGURE 4. Begonia papulifolia. A, Habit; B, Close-up of leaf surface; C, Stipule; D, Male inflorescence; E, Male inflorescence and fruit; F, Male flower; G, Fruit; H, Cross-section of fruit. All photos from SFC 5702 by C.Y. Ling.