Begonia jackiana M.Hughes sp. nov. § Bracteibegonia urn:lsid:ipni.org:names:77151642-1 Figs 4, 7 Diagnosis Begonia jackiana is unique amongst Sumatran members of sect. Bracteibegonia in its small leaf size (2.5–5.5 × 1.2–2.5 cm) and bristles on the upper leaf surface. Its shares a dentate-denticulate hairy leaf margin with B. bracteata Jack, which differs in being densely softly pilose above. Etymology The epithet commemorates the Scottish botanist William Jack [1795–1822], as this species was found whilst following in Jack’s footsteps in Bengkulu Province (Hughes & Girmansyah 2011a). Type SUMATRA: Bengkulu, Kapahiang, 680 m, 14 Aug. 2010, Girmansyah & Hughes DEDEN 1494 (holo-: BO, iso-: E). Additional material SUMATRA: Bengkulu, Kapahiang, 680 m, 14 Aug. 2010, Girmansyah & Hughes 1493 (BO, E). Description Small colony forming caulescent erect terrestrial herb, 15–20 cm tall; stem erect, rooting at the lower nodes, densely hairy, internodes 1–3.5 cm long. Stipules semi-persistent, with sparse hairs on the keel and margin, narrowly lanceolate, 4 × 1–2 mm. Leaves: petiole 0.4–1 cm long, terete, densely hairy; lamina small, elliptic to rhomboid, membranous, asymmetric, 2.5–5.5 × 1.2–2.5 cm, basifixed, base truncate on one side auriculate on the other, upper surface with evenly spaced bristles between the veins, underside densely hairy on the veins, hairs shorter than the bristles above, venation pinnate to palmatepinnate; margin dentate, slightly hairy, teeth 3–5 mm apart and c. 2 mm long; apex acute. Inflorescences terminal, total length 3–5 cm, a cyme of sub-umbellate cymes, branching 2 times, few (c. 5) flowered, bisexual, protandrous; primary peduncle 1 cm long, sparsely hairy; bracts deciduous, elliptic-lanceolate, 3.5 × 1.5 mm wide, margin fimbriate. Male flowers: pedicel 10 mm long, with scattered hairs; tepals 4; outer tepals orbicular-obcordate, 11 mm in diameter, pinkish-white with deep pink on the reverse, upper tepal darker, not fleshy, with hairs denser towards the base, base slightly cordate becoming truncate when open, margin entire; inner tepals elliptic, 7 × 3 mm wide, white; androecium yellow, loosely globose, symmetric, stamens c. 25, on a short column; filaments subequal, 1.25–1.5 mm long, free; anthers narrowly oblong, c. 1.75 mm long, connective slightly retuse, hooded, dehiscing through slits about half the length of the anther, slits on the outer face of the anther. Female flowers: bracteoles present, lanceolate, 4 × 1.5 mm, fimbriate, 1–2 mm from the base of the ovary; pedicel 8–9 mm long, sparsely hairy; ovary pale pink, wings darker, with scattered stiff bristles on the capsule; capsule ellipsoid, 5 × 3 mm, 3-locular, placentae bifid; wings 3, equal, triangular, c. 3 mm wide; tepals 5, subequal, elliptic, c. 8 × 4 mm, upper petal pink, deeper pink on reverse, lower 4 tepals paler pink to white, glabrous, margin entire, persistent and closed during fruit ripening; stigma yellow, crescent shaped with the ends spiralled slightly, styles 3, deciduous. Fruit 1–2 in number, recurved at maturity on a c. 10 mm pedicel, turning red before drying brown, total size 13 × 10 mm; capsule elliptic, 8 × 4 mm, glabrous; wings subequal, triangular, 4 × 8 mm; apex obtuse to truncate. Distribution and habitat Only known from the forests in Kapahiang Regency in Bengkulu (Fig. 4). Found growing in small colonies by the roadside, near a damp ditch in the shade of other herbs. Conservation status The fact that this species has some ability to cope with secondary habitats may make it less likely to become threatened. However it is only known from one locality, and hence is best considered as Vulnerable under VUD2 (IUCN 2012) as the only known locality is not in a gazetted protected area.

Published as part of Hughes, Mark, Girmansyah, Deden & Ardi, Wisnu Handoyo, 2015, Further discoveries in the ever-expanding genus Begonia (Begoniaceae): fifteen new species from Sumatra, pp. 1-40 in European Journal of Taxonomy 167 on pages 16-17, DOI: 10.5852/ejt.2015.167, http://zenodo.org/record/3805815