Begonia lilliputana M.Hughes sp. nov. § Reichenheimia

urn:lsid:ipni.org:names:77151648-1

Figs 4, 13

Diagnosis

This diminutive species differs from the only other known Sumatran rheophytic begonia, Begonia fluvialis (see above), in its smaller stature (leaves 3 cm long, not 8–15 cm long), by lacking bristles at the petiole apex and having barely peltate leaves (not minutely cordate). The other geographically nearest rheophytic species from Peninsular Malaysia [ B. abdullahpieei Kiew, B. aequilateralis Irmsch., B. klossii Ridl., B. perakensis King, B. rhoephila Ridl. and B. rhyacophila Kiew (Irmscher 1929; Kiew 2005; King 1902; Ridley 1917)] all belong to Begonia sect. Platycentrum and differ in being larger plants with 2-locular fruits.

Etymology

The name is derived from the adjective lilliputian (English) meaning very small, derived from the name of the fictional island nation of Lilliput.

Type

SUMATRA: Aceh, Soraya Research Station, 50 m, 3 Feb. 1999, Argent 9938 (holo-: A).

Description

Diminutive acaulescent lithophytic riverine herb growing on rocks near waterfalls, c. 8 cm in height; stem rhizomatous, 2 mm in diameter, internodes 2–4 mm long. Stipules persistent, glabrous, 4–5 × 2 mm, lanceolate, with a filiform extension at the apex. Leaves: petiole 3 cm long, tomentose, crosssection unknown, rapidly becoming sub-glabrous with age; lamina minutely peltate, base rounded, elliptic-rhomboid, subsymmetric, c. 3 × 1 cm, upper surface glabrous, lower surface with dense hairs on veins only, venation palmate-pinnate, veins prominent above and below; margin minutely and sparsely denticulate; apex acute. Inflorescences axillary, total length 6–8 cm, cymose, branching 2–3 times, 3–4 flowered, bisexual, protandrous; primary peduncle 5–7 cm long, with sparse long hairs; bracts minute, elliptic-lanceolate with an extended tip, 1–1.5 mm long. Male flowers: pedicel 10 mm long, with scattered glandular hairs; tepals 4; outer tepals ovate-elliptic, 3 × 2 mm, pink or white, fleshy, with scattered glandular hairs on the outside, margin with a distinct rim; inner tepals elliptic, 2 × 1 mm; androecium globose; stamens c. 60; filaments equal, 0.5 mm long, fused at base into a column; anthers about as long as the filaments; ellipsoid-obtriangular, 0.5 mm long, connective slightly retuse, dehiscing through slits about half the length of the anther, with one slit on each side of the anther. Female flowers unknown. Fruits solitary, recurved on a 13 mm long pedicel; total size 10 × 6 mm; wings roundedtriangular, 3 × 6 mm, equal; capsule spherical, 3–4 mm in diameter, glabrous; apex obtuse.

Distribution and habitat

Currently known only from the type locality near the Soraya Research Station (Fig. 4) in Gunung Leuser National Park, where it grows as a rheophyte tightly attached to rocks at the base of waterfalls, in the shade of overhanging trees.

Conservation status

Begonia lilliputana is assessed as Data Deficient (IUCN 2012) as its full range within the Gunung Leuser National Park is unknown; the Soraya Research Station is on the southernmost edge of the core reserve.