Begonia latifolia S.Julia & C.Y.Ling, 2022

Julia, S., Kiew, R. & Ling, C. Y., 2022, ADDITIONS TO THE BEGONIA FLORA OF SARAWAK, BORNEO, I: TWELVE NEW SPECIES AND A NEW RECORD, Edinburgh Journal of Botany 79 (410), pp. 1-46 : 20-22

8. Begonia latifolia S.Julia & C.Y.Ling , sp. nov.

Similar to Begonia celata S.Julia & Kiew in its habit but differs in having longer internodes, 2–5.5 cm (versus 0.7–2 cm long); much larger bracts, 10–20 × 15–25 mm (versus 6–11 × 3–5 mm); fewer bracteoles, up to 5 pairs (versus 12 pairs); wider lower bracteoles, 6–10 mm (versus 4 mm wide), and upper bracteoles, 4–8 mm (versus 2–3 mm wide); fewer stamens, 15–20 (versus 28–35); and smaller female flowers with ovary 4–5 × 5–6.5 mm (versus 6–7 × 8–9 mm).

– Type: Malaysia, Borneo , Sarawak, Kapit District , Baleh , Kakap Camp , Sungai Bekakap, 1°21′55′′N, 113°43′31′′E, 9 iii 2016, Ling et al. SFC 5907 (holotype SAR!, isotype KEP!). Figure 9 .

Creeping herb, 4–8 cm long. Stem, stipule and petiole densely hirsute, hairs c. 3 mm long, magenta, sometimes white on juvenile plants. Stems red brown, little branched, succulent, 3.5–6 mm thick, internodes 2–5.5 cm long, slightly thicker at nodes. Stipules pale green to yellow green, sometimes reddish at base, broadly ovate, 1.3–2.8 × 1.4–2.7 cm, keeled, margin ciliate, apex acute or rounded, persistent. Leaves alternate, distant, oblique, held horizontally, upper lamina surface and lower veins densely hirsute, hairs magenta, sometimes white on upper leaf surface and on juvenile plants, c. 3 mm long; petioles red brown, (1.5–) 3–7.5 cm long, terete or slightly grooved above; lamina dark green above, pale green beneath, in life succulent, matt, asymmetrical, ovate, 5.5–9.5 × 6.5–12 cm, broad side 3.6–8 cm wide, base cordate, sometimes overlapping, basal lobes 1–2 cm long, margin minutely dentate and ciliate, apex acuminate, acumen 3–5 mm long; venation pinnate-palmate, veins green, above reddish near base, beneath pale green, pale brown near base, 4 pairs from the base and 2 veins on either side of the midrib, 1 or 2 veins in basal lobe, slightly impressed above, prominent beneath. Inflorescences protogynous, in upper leaf axils, racemose to 3–5 cm long, peduncle glabrous, 2.3–2.5 cm long; bracts similar to stipules, pale green or yellow green, reddish at base, ovate, 10–20 × 15–25 mm, margin ciliate, persistent; bracteoles to 5 pairs, lower bracteoles pale green, reddish at base, 9–12 × 6–10 mm, margin ciliate, sometimes sparsely hirsute, hairs red, upper bracteoles pale green, reddish at base, ovate 4–6 × 4–8 mm, margin ciliate or irregularly serrate, apex emarginate, persistent. Male flowers: pedicel white, 8–10 mm long, glabrescent; tepals 4, pink, deep pink near base, glabrous, margin entire, apex broadly acute to rounded, outer two tepals elliptic, 9–11 × 5–6 mm, inner two tepals lanceolate, 7–9.5 × 1.5–2 mm; stamens 15–20, cluster conical, sessile; filaments pale yellow, c. 1 mm long; anthers pale yellow, obovate, c.1.5 × 1 mm, apex emarginate. Female flowers: sessile, enclosed by 2 or 3 bracteoles; ovary white or pale green, obovate, ovary including the wings 4–5 × 5–6.5 mm, glabrous, wings 3, unequal, locules 3, placentas 2 per locule; tepals 5, pinkish, glabrous, margin entire, apex acute, outer three tepals elliptic, 8–8.5 × 4–5 mm, inner two tepals narrowly elliptic to lanceolate, 8–9 × 2–2.5 mm; styles 3, pale yellow, c. 3 mm long, divided to base; stigma pale yellow, anchor-shaped, papillose forming a continuous twisted band. Capsule not seen.

Distribution. Malaysia ( Sarawak). To date, known only from Kapit District (see Figure 1 ).

Habitat. Riparian forest on rocks and stream banks, at elevations to 313 m.

Etymology. Latin, lati - (‘broad’) and folius (‘leaf’), referring to its lamina broader than long.

Begonia latifolia is uncommon where it occurs. Compared with Begonia bosuangiana from Sabah, this species is larger, with stem 4–8 cm long (versus low herb to 4 cm tall); longer internodes, 2–5.5 cm (versus 1–1.5 cm long); larger lamina, 5.5–9.5 × 6.5–12 cm (versus c.5 × 5.3 cm); and conspicuously larger lower bracteoles, 4–12 × 6–10 mm (versus 1–2.5 × 1–2 mm).

Figures

Figure 1. Distribution of Begonia papyraptera and the 12 new species of Begonia recorded from Sarawak and described in this article.

Figure 9. Begonia latifolia S.Julia & C.Y.Ling, sp. nov. A, Habit and habitat; B, stipule; C, juvenile leaf; D, inflorescence; E and F, male flower; G and H, female flower; I, cross-section of ovary. All photographs of the type specimen, Ling et al. SFC 5907, taken by C. Y. Ling.