Begonia bajik S. Julia & C. Y. Ling 2022, sp. nov.

1.Begonia bajik S.Julia & C.Y.Ling, sp. nov.

Most similar to Begonia erythrogyna Sands in its matt leaves, paniculate male inflorescence and large red capsules, but B. bajik has longer stipules, 2.5–4.3 cm (versus 1.5–2 cm long); shorter petioles, 2.5–5 cm (versus 5.5–14.5 cm long); longer inflorescences, 18–28 cm (versus 7–14 cm long); smaller tepals of female flower, 7–11 × 3–5.5 mm (versus 18–20 × 7–9 mm); and larger capsules, 30–43 × 25–43 cm (versus 28–32 × 18–20 mm). – Type: Malaysia, Borneo, Sarawak, Kapit District, Baleh, Kakap Camp, Tributary of Sungai Melatai, 1°20′11′N, 113°46′12′E, 9 iii 2016, Ling et al. SFC 5909 (holotype SAR!, isotype KEP!). Figure 2 .

Cane-like herb up to 1 m tall. Stems little branched, dull green to reddish, internodes 2.5–8(–13) cm long, 5–8 mm thick, glabrous, slightly thicker at nodes. Stipules pale green to reddish brown, glabrous, triangular, 2.5–4.3 × 1.2–1.5 cm, margin entire, rather stiff and rolled backwards, apex setose, seta 2–3 mm long, caducous. Leaves alternate, distant, held vertically when young; held horizontally when older, oblique; petioles red brown, glabrous, 2.5–5 cm long; lamina plain, dark green with silvery sheen above, glabrous, magenta below, young lamina sometimes covered with irregular white spots above, in life succulent and thick, matt, asymmetrical, broadly ovate, 12.5–19 × 10–13 cm, broad side 6.6–9 cm wide, base cordate, basal lobes 4–5 cm long, margin minutely dentate, apex acuminate, acumen 1.5–2.5 cm long; venation palmate-pinnate, 6–11 veins on either side of the midrib, branching 3 or 4 times, 4 veins in basal lobe, green except near base above, magenta below, glabrous, sunken above, prominent below. Inflorescences protogynous, axillary in upper leaves, glabrous, 1 or 2 female flowers at the base, panicle of male flowers terminal of uppermost leaf axil, rachis 15–23 cm long, peduncle 3–5 cm long; bracts (young) pale green, lanceolate c.17 × 5 mm, caducous, bracteoles pale green or sometimes reddish, reddish on upper half towards apex, lanceolate, c.16 × 5 mm. Male flowers: pedicel red, pale green at base, 4–5 mm long; tepals 2, deep red, broadly ovate, glabrous, margin entire, apex rounded, 4–4.5 × 4–5 mm; stamens 24–26, cluster conical, subsessile; filaments 1–1.4 mm long; anthers pale yellow, obovate, c.1.2 × 0.6 mm, apex emarginate or rounded. Female flowers: pedicel pale green, 10–12 mm long, glabrous; ovary pale green, pink on locules and wings, ovary including wing triangular, 11–13 × 13–14 mm, glabrous, wings 3, equal, locules 3, placentas 2 per locule; tepals 5, pink-tinged pale green at margin, outer four tepals ovate, 8–11 × 5–5.5 mm, margin minutely dentate to entire, apex acute, inner tepal narrowly elliptic, 7–8 × 3 mm, margin entire, apex broadly acute; styles 3, pale yellow, c. 2 mm long, divided to base, Y-shaped; stigma pale yellow, papillose forming a continuous twisted band. Capsules 1 or 2, axillary, triangular in outline or lanceolate, deep red to dark maroon, 3–4.3 × 2.5–4.3 cm, glabrous, locules 3, placentas 2 per locule, wings 3, equal, acute proximally, sharply pointed distally, 1.5–2.2 cm wide, dehiscing between the locule and wing, pendent on thin red pedicel, 2.5–4.1 cm long.

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

Habitat. Near seasonal creeks in disturbed hill forest at elevations to 953 m.

Etymology. From the native Iban word bajik, which means ‘beautiful’, alluding to the attractive appearance of this species.

Begonia bajik is uncommon and known only from the type locality. It is striking in its large triangular fruits, in which the width almost equals the length and the wing tips are pointed.

This species resembles smaller plants of Begonia sirukitii S.Julia & C.Y.Ling in its leaf characters, inflorescence type and male flowers, but B. bajik can be distinguished by its female flowers and fruits.

Compared with Begonia alabensis Kiew, B. bajik has larger stipules, 2.5–4.3 × 1.2–1.5 cm (versus 2.5 × 0.8–10 cm); shorter petioles, 2.5–5 cm (versus 10.5–15 cm long); more numerous veins, 6–11 pairs (versus 4 pairs); and longer panicles of male flowers, 15–23 cm (versus short cyme to 9 cm long).

This species is also similar to Begonia bekakapensis C.Y.Ling & S.Julia in its succulent, matt and asymmetrical leaf. However, Begonia bajik differs in its stiff stipules with margins rolled backwards; venation dense, 6–11 (versus 4 or 5) veins on either side of the midrib, and 4 (versus 2 or 3) veins in basal lobe; inflorescence paniculate (versus racemose), 15–23 cm (versus 2–5 cm) long; pedicel of male flower 4–5 mm (versus 10–12 mm) long, the tepals 4–4.5 × 4–5 mm (versus 6–8.5 × 6.5–7 mm), with fewer stamens, 24–26 (versus 45–56); female flower with longer pedicel, 10–12 mm (versus 4–5 mm long), ovary triangular with sharply pointed wing tips (versus lanceolate with rounded wing tips), 11–13 mm (versus 18–20 mm) long; and wider capsule, 2.5–4.3 cm (versus 1.8–2.1 cm wide), and longer fruit pedicel, 2.5–4.1 cm (versus 1.1–1.2 cm long).