Alangium borneense Merr.

Dewilde, W. J. J. O. & Duyfjes, B. E. E., 2017, Taxonomy of Alangium section Conostigma (Alangiaceae), Blumea 62 (1), pp. 29-46 : 30

1. Alangium borneense Merr.

Alangium borneense Merr.(1922) 342. — Type: Agama 1022 (holo PNH†;iso BM BM000944961 , K K000704827 , L L0009820 , P P04552684 ), Borneo, Sabah, Batu Lima , Nov. 1920, fl.

Tree to 18 m tall; twigs brown, 3–4 mm diam, at apex hairy; leaf bud in-curved, densely hairy, hairs c. 0.5 mm long. Leaves: petiole 0.5–1 cm long; lamina drying greenish brown, veins (sparsely) hairy below, narrowly elliptic, 10–23 by 3–6(–8) cm, base almost symmetric, (rounded or) short cuneate, apex acute and apiculate to 1 cm; veins pinnate, 10–15 on each side, loop-veined at least in upper third of blade, tertiary venation thin, (sub)scalariform. Inflorescences hairy, of 1 or 2 (or 3) main branches (peduncles) from the leaf axil, each few-branched, 2 –7-flowered; peduncle (s) 1–10 mm long. Flowers densely appressed hairy; pedicel 3–5 mm long; corolla in bud 10–17 mm long, base not swollen, apex acute; ovary and calyx 4 –6 mm long, ribbed; limb (sub)erect 1–1.5 mm long, at margin c. 4 mm wide, (sub)truncate or obscurely toothed; petals 5 or 6, inside glabrous, 10–15 mm long; stamens 5 or 6, filament glabrous, c. 5 mm long, somewhat flattened, without thickened portion near base, anther 5–9 mm long, connective glabrous; style densely appressed hairy for the larger part, 7–15 mm long, stigma conical. Fruit 1 (or 2) per infructescence, ripening pink or red, densely minutely hairy (hairs yellowish green, c. 0.1 mm long), (narrowly) ellipsoid, narrowed at base and apex (± fusiform), 20–30 by c. 14 mm, finely ribbed; calyx remnant narrow or contracted, subtruncate.

Distribution — Borneo ( Brunei, Sarawak, Sabah (most collections), W & E Kalimantan).

Habitat & Ecology — Lowland mixed dipterocarp forest, flatland or undulating country, along rivers and hillside, also in swampy forest; basalt, sandy clay, podsoil, and (yellow) sandy soil; from sea level to 600 m altitude; flowering and fruiting all year round.

Field-notes — Stilt-roots and buttresses recorded; bark smooth; fruits edible, green ripening pinkish or red.

Vernacular names — Kagukapan (Sungei Kinabatangan), Satu Inchi, Midong (Iban), Kondolon, Aru (Kayal), Jadam.

Note — Alangium borneense resembles A. mezianum ; the latter is generally stouter in all parts (but not the fruit), its tomentum of twig apex and leaf bud is shorter (hairs 0.2–0.3 mm only), its leaf bud is (almost) straight, and its filaments are hairy at apex. In A. borneense the leaf bud is characteristically strongly in-curved and densely woolly hairy, not allowing to see the juvenile lateral veins, and its filaments are glabrous.