Begonia ignota C.Y.Ling & Kiew, 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 : 10-11

4. Begonia ignota C.Y.Ling & Kiew , sp. nov.

Similar to Begonia bintang Rimi in its habit, leaf shape and single-flowered female inflorescence, but B. ignota can be distinguished by its longer internodes, 2–7.5 cm (versus 0.4–1.7 cm long); larger stipules, 14–18 × 9–10 mm (versus c.10 × 3–4 mm); larger oblanceolate leaves, 14–23 × 5–10 cm, with basal lobe 4–7 mm long (versus narrowly obovate, 6.5–12.5 × 2–3 cm, with an undeveloped basal lobe); larger bracts and bracteoles, 13–15 × 7 mm and c.10 × 4 mm, respectively (versus bracts c.2 × 1.8 mm and bracteoles c.2 × 1 mm); larger oblong ovary, c.22 × 12 mm (versus ovary turbinate, c.4 × 7–14 mm); and larger oblong capsule, 22–30 × 10–15 mm (versus turbinate capsule, 4–5 × 15–20 mm).

– Type: Malaysia, Borneo , Sarawak, Julau District , Lanjak Entimau Wildlife Sanctuary , Ulu Mujok, Sungai Jungin, 1°42′15′′N, 112°04′25′′E, 20 v 2016, Ling & Dino SFC 5920 (holotype SAR!, isotype KEP!). Figure 5 .

Erect herb to 50 cm tall. Stems, stipules and lower leaf surface tomentose, hairs pale brown. Stems brown, internodes 2–7.5 cm long, 4–6 mm thick. Stipules pale green to yellow green, ovate, 14–18 × 9–10 mm, margin entire, keeled, apex setose, seta 1–2 mm long. Leaves alternate, distant, slightly oblique, asymmetrical, held horizontally; petioles brown, 0.4–0.8 cm long, grooved above; lamina glabrous, plain dark green above, pale green beneath, slightly falcate, in life succulent, matt, oblanceolate, 14–23 × 5–10 cm, broad side 3–6 cm wide, base unequal, broad side rounded with basal lobe 4–7 mm long, narrow side with cuneate base, margin minutely dentate, apex acuminate, acumen 1–2 cm long; venation pinnate, veins concolorous, prominent on both surfaces, 4–7 veins on either side of the midrib, 1 or 2 veins in basal lobe. Inflorescences protogynous, axillary in the lower leaf axils, female inflorescence simple dichasium; bracts pale yellow green, ovate, 13–15 × 7 mm, margin entire, apex acuminate, persistent; bracteoles similar to bracts but smaller, c.10 ×

4 mm, persistent. Male flowers: not seen. Female flowers: pedicel white with a hint of yellow, c. 7 mm long, tomentose; ovary white, tinged pale green on the wings, densely tomentose, oblong, ovary including the wings c.22 × 12 mm, wings 3, equal, locules 3, placentas 2 per locule; tepals 5, white tinged pale green at apex, narrowly elliptic, c.14 × 5 mm; styles 3, pale yellow, c. 3 mm long, divided to base, anchor-shaped; stigma yellow, papillose and pale yellow forming a continuous twisted band. Capsules pale green, locules densely tomentose, hairs brown, oblong, 22–30 × 10–15 mm, locules 3, wings 3, equal, acute proximally, rounded to concave distally, 4–7 mm wide, thinly fibrous, dehiscing between locule and wing; pedicel stiff, perpendicular to stem, 5–6 mm long.

Distribution. Malaysia ( Sarawak). To date, known only from Lanjak Entimau Wildlife Sanctuary (see Figure 1 ).

Habitat. Riparian forest along a small stream with occasional mudstone boulders, to 131 m elevation.

Etymology. Latin, ignotus (‘unknown’), referring to this nondescript erect begonia without special features, which remained unnoticed and unknown until now.

The unusual character of this species is the capsule that is held perpendicular to the stem rather than hanging pendent as is usual. Among Bornean begonias, this type of capsule is seen only in Begonia joffrei S.Julia and B. matangensis S.Julia & Kiew. Both also have an oblanceolate ovary with silky hairs and green-yellowish tepals. However, Begonia joffrei can be differentiated from this species in having a bushy habit with stem to 1 m tall, leaf oblique, alternate on erect stem but then on branched stems the leaves appearing opposite. In its habit, the species is similar to Begonia matangensis , but in B. matangensis , the upper leaves are opposite whereas the lower leaves are arranged alternately, and the lamina is not oblique.

Figures

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

Figure 5. Begonia ignota C.Y.Ling & Kiew, sp. nov. A, Habit; B, stipule; C and D, female flower; E, young capsule; F, cross-section of capsule. All photographs of the type specimen, Ling & Dino SFC 5920, taken by C. Y. Ling.