Begonia alabensis Kiew, 2015

Repin, Rimi, Sang, Julia, Kiew, Ruth & Mujih, Handry, 2015, Eleven new species of Begonia (Begoniaceae) from the Crocker Range, Sabah, Malaysia, Phytotaxa 208 (1), pp. 1-20 : 3-5

1. Begonia alabensis Kiew , spec. nov. ( Figure 2 )

Sect. Petermannia

Similar to B. inostegia Stapf (1894: 166) in its long petioles, in lamina shape and venation and large fruits dangling on long slender pedicels but it is different in its stipules and bracts that have an entire margin (not fimbriate as in B. inostegia ), its large stipules ca. 25 mm long (not 8.5–15 mm long), longer petioles 10.5–15 cm long (not 7.5–9.5 cm long), laminas that are longer than wide, 15.5–17.5 × 10.5–13 cm (not almost as wide as long, 12–14 × 10–13.5 cm), in its few small-flowered male inflorescences (not many-flowered with larger flowers) and in its much larger fruits, ca. 33 × 23 mm, that are narrowed to the apex and have a pedicel ca. 36 mm long (not 10.5–17 × 15 mm and truncate or rounded at the apex with a fruit pedicel ca. 15 mm long).

Type:— MALAYSIA. Borneo. Sabah. Tambunan District: Crocker Range Park, Alab sub-station, Minduk Sirung trail, before the 0.5 km point, Sept 2012, Lens FL 72. (holotype SNP!; isotype SAN!) .

Cane-like begonia, 60–100 cm tall, woody at the base. Stem green, 6–7 mm thick, hollow when dried; internodes ca. 12.5 cm long, glabrous, much branched, nodes swollen. Stipules light green, glabrous, lanceolate, ca. 25 × 8–10 mm, keeled, margin entire, apex acuminate, acumen ca. 4 mm long, persistent. Leaves alternate, oblique, distant, held horizontally; petiole reddish, glabrous, 10.5–15 cm long, grooved above; lamina dark green above, dark purple beneath, plain, fleshy in life and papery when dry, glossy, broadly ovate, asymmetric, 15.5–17.5 × 10.5–13, broad side 7.5–9.5 cm wide, base cordate, basal lobes 5–6.5 cm wide, broadly rounded, margin slightly scalloped and minutely dentate, apex acuminate, acumen 1.5–2.2 cm long; venation palmate-pinnate, veins reddish, glabrous, 4 veins on either side of the midrib, 1 pair at the base, 3 veins in basal lobe, impressed above, slightly prominent beneath. Inflorescences protogynous, terminal on lateral branches, glabrous; female inflorescences cymose with 3 flowers; male inflorescences ca. 5 cm long with a few short cymose branches, peduncle ca. 4 cm long, white. Bracts: green, lanceolate, 17–22 × 3–4 mm (on female flower), margin entire, caducous; bracteoles on female flowers light green, lanceolate, ca. 14 × 4 mm, glabrous, caducous; on male flowers hemispherical, ca. 0.5 mm long, persistent. Female flower: pedicel 25–37 cm long, light green; ovary reddish-green, glabrous, spindle-shaped, 13–18 × 6–8 cm, wings 3, equal, locules 3, placenta 2 per locule with many ovules on both surfaces; tepals 5, isomorphic, 14–17 × 6, oval, white tinged pink, margin entire, apex acute; styles 3, yellow, ca. 4 mm long, divided to base, deeply Y-shaped with twisted tips; stigma yellow, papillose forming a continuous twisted band. Male flower: pedicel pale yellow, 2–5 mm long; tepals 2, white tinged pink, glabrous, oval, ca. 4 × 2 mm, margin entire, apex acute; stamen ca. 18, cluster conical, subsessile; filament yellow, ca. 0.4 mm long; anthers yellow, oblong or obovate, ca. 0.5 × 0.3 mm, apex emarginate. Capsule dangling on a fine thread-like pedicel ca. 36 mm long; fruit ca. 33 × 23 mm, glabrous, locules narrowly spindle shaped, wings 3, equal, narrowed proximally, increasing in size for the three quarter of the fruit, then narrowed abruptly to the base of the styles, ca. 7 mm wide, thinly fibrous, dehiscing between the locule and wing. Seed: barrel-shaped, ca. 0.3 × 0.1 mm, columnar cells more than half the length of seed.

Distribution: — MALAYSIA. Borneo. Sabah, Tambunan District. Endemic in Crocker Range Park.

Habitat: —Primary cloud forest, steep slope along river, 1800–1865 m elevation.

Etymology: —Named for the locality, Gunung Alab, from where it was first collected.

Additional specimens examined: — MALAYSIA. Borneo. Sabah. Tambunan District: Crocker Range Park – Alab substation, Rossiti & Kamin SNP 36819 (KEP, SAN, SNP), km 45 Penampang-Tambunan Road, Rossiti & Yau KNP A16202 (SNP); Mindul Sirung Trail, Lens FL 70 (SNP), FL 78 (SNP).

Notes: —Its fruit is unusual in its long pedicels and the wings being narrowed to the apex. Hollow stems have not previously been remarked upon in begonias, but in this species the stem becomes hard and woody and at least in dried specimens is hollow.

Figures

FIGURE 2. Begonia alabensis. A. Habit with fruits; B. Male inflorescence; C. Female flower; D. Opened female flower. All photos by Rossiti Karim.