Begonia dasycaulis Kiew & C.Y.Ling, 2018

Yiing, Ling Chea, Sang, Julia & Kiew, Ruth, 2018, Begonia species (Begoniaceae) from Gunung Penrissen, Sarawak, Borneo, including two new species and a new subspecies, Phytotaxa 381 (1), pp. 12-21 : 13-15

2. Begonia dasycaulis Kiew & C.Y.Ling , sp. nov. ( Figure 1 )

Sect. Petermannia

The species is most similar to Begonia joffrei Kiew & S.Julia (2015: 28) in its habit, apparent opposite leaves, inflorescences on short branches and male flowers with two small tepals. It is differentiated by its long soft hairs perpendicular to stem (vs. hispid appressed in B. joffrei ); its shallowly cordate lamina base (vs. very unequal with the broader side auriculate), narrower basal lobes 3–5 mm long (vs. 7–10 mm long), its inflorescence a compact dichasium with one female flower at the base and male flowers above (vs. male and female flowers on separate inflorescences); hairy tepals (vs. glabrous tepals); 5 female tepals (vs. 4) and ovate fruits, 11–17 × 10–17 mm (vs. fruits oblong, ca. 20 × 15 mm). Type: — MALAYSIA. Borneo, Sarawak, Padawan District: Gunung Penrissen, 3 December 2017, Julia et al. SFC 5587 (holotype SAR!; isotype KEP!).

Erect, sparsely branched herb to 1.5 m tall, growing in big clumps. Stem, stipule, petiole, lamina, fruit and outer tepal surface covered with dense, long soft brownish hairs, those on stem perpendicular, 5–6 mm long. Stems dark brown or red-brown, terete, 6–8 mm thick, internodes 3.5–12.5 cm long, swollen at the nodes. Stipules lanceolate, 9–18 × 4–7 mm, strongly keeled, margin entire, apex setose, seta to 2 mm long, caducous. Leaves alternate, appearing sub-opposite towards the top of the stem, not oblique, sometimes slightly falcate, held horizontally; petioles reddish brown, 0.8–1.4 cm long, grooved above; lamina plain green above, paler beneath, in life succulent, glossy, obovate, 11–20 × 3.5–7.5 cm, broad side 2.2–4.6 cm wide, base shallowly cordate, basal lobes 3–5 mm long, margin finely toothed, apex acuminate, 1–1.5 cm long; venation pinnate, sunken above, prominent below, 6–7 veins on either side of the midrib, branching 1–2 times, in life veins pale green above, reddish below, 1–2 veins in the basal lobe, tertiary veins reticulate, slightly prominent on both surfaces. Inflorescences protogynous, produced on a short branch 0.5–1.5 cm long, opposite the leaf, compact dichasium with 1 female flower at the base and male flowers above, 0.3–0.4 cm long. Bracts reddish, lanceolate, 7–10 × 3–4 mm, margin entire, apex setose, seta to 2 mm long, caducous; bracteoles lanceolate, 5–12 × 3 mm, caducous. Male flowers: pedicel reddish, 7–8 mm long, glabrous; tepals 2, reddish or whitish, dark red near the base, ovate, 6–8 × 4–6 mm, margin entire, apex acute; stamens 26–33, cluster conical, torus ca. 0.8 mm long; filaments pale yellow, 0.8–1 mm long; anthers pale yellow, obovate or ovate, ca. 1 × 0.8 mm, apex emarginate. Female flowers: pedicel reddish, 6–8 mm long; ovary pale green or yellowish green, 9–11 × 10–14 mm, wings 3, equal, pale green with a conspicuous red line between the locules and the wing, wing tip rounded, locules 3, placentas 2 per locule; tepals 5, yellowish, ovate, 7–10 × 5–10 mm, margin entire, apex acute; styles 3, yellowish green or pinkish, ca. 1 mm long, divided to base, Y-shaped; stigma yellowish or pinkish, papillose forming a continuous twisted band. Fruit single, pale green with a dark red line between the locules and between the locules and wings, ovate, 11–17 mm long, 10–17 mm wide across the wings, locules 3, wings 3, subequal, 3–5 mm wide, thinly fibrous, conspicuously unequal at the base, rounded proximally and distally, wings dehiscing between locule and wing; pedicel pendent, 6–12 mm long, reddish or pinkish.

Distribution: —Endemic in Borneo. So far known only from Gunung Penrissen, Padawan District, Sarawak.

Habitat: —In hill forest at elevation to 1000 m. Growing on rocky slopes with a thin layer of leaf litter or sometimes on mossy rocky slopes in semi-shaded areas.

Etymology: —Greek, dasys = hairy; caulon = stem.

Notes: —The whole plant is conspicuously hispid with long hairs to 5–6 mm long and by its very small capsule that in life has striking red lines. Also notable was that most leaves in the population were eaten by insects (usually leaves of begonias in Borneo are free of insect damage). Although this species is most similar to B. hirtitepala S. Julia & Kiew (2016: 266) in its indumentum, B. dasycaulis can be distinguished from B. hirtitepala by its leaf arrangement, leave shape, basal lobes, inflorescence type, bract, glabrous tepals on male flower and the number of tepals in female flower.

3. Begonia lailana Kiew& Geri (2003: 117) : Kiew et al. Guide to Begonias of Borneo (2015) 158 ; Type:— MALAYSIA, Borneo, Sarawak: Bau , Gunung Kawa , 12 November 2002, Geri et al. SBC 3753 (holotype SAR!; isotypes K!, L!, SAN!, SBC!, SING!). Synonym: Begonia oblongifolia Stapf auct. non Ridley (1906: 251) .

Sect. Petermannia

Distribution: —Endemic in Kuching Division, Sarawak.

Specimen examined: — MALAYSIA. Borneo, Sarawak, Padawan District: Gunung Penrissen, 3 December 2017, Julia et al. SFC 5590 (SAR!, KEP!).

Habitat: —Lowland mixed dipterocarp forest, on river banks or at the base of limestone hills in light shade.

Etymology: —Named after Datuk Amar Puan Sri Dr Hajjah Laila Taib, the late wife of 4th Chief Minister of Sarawak.

Notes: —The species is commonly sold in local markets in Kuching as a vegetables eaten as ‘ulam’ (local salad) or used as a food flavour for its sour taste.

Figures

FIGURE 1. Begonia dasycaulis A. Habit; B. Stipule and stem; C. Inflorescence and fruits borne along the short branch; D & E. Male flower; F & G. Female flower; H. Fruit; I. Cross-section of capsule.All photos from SFC 5587 by Ling Chea Yiing.