Alangium mezianum Wangerin

Dewilde, W. J. J. O. & Duyfjes, B. E. E., 2017, Taxonomy of Alangium section Conostigma (Alangiaceae), Blumea 62 (1), pp. 29-46 : 38

12. Alangium mezianum Wangerin

Alangium mezianum Wangerin (1907) 338; (1910) 15, f. 3f, j. — Type: Hose (Haviland) 2885 (holo L L0009821 ; iso BO, K 2 sheets K000704824 , K000704825 , SING), Sarawak, Kapit , Rejang, July 1885, fl .

(Shrub) tree to 30 m tall; twigs brown, 3–5 mm diam, at apex short hairy; leaf bud straight, densely short hairy, hairs c. 0.3 mm long. Leaves: petiole 1–2 cm long; lamina drying brown, glabrous (midvein below somewhat short-hairy), narrowly elliptic, (15–)20–30 by 6–12 cm, base symmetric, rounded or short-cuneate, apex rather broadly acuminate to c. 1 cm; veins pinnate, 10–15 on each side, loop-veined especially towards apex of lamina; tertiary venation thin, ± scalariform. Inflorescences minutely hairy, hairs c. 0.2 mm long, of 1 (or 2) branches (peduncles) from the leaf axil, each few-branched, 2–4-flowered; peduncle (s) (2–) 5–10 mm long. Flowers minutely hairy (hairs c. 0.3 mm long); pedicel 2–3 mm long; corolla in bud c. 15 mm long, base not swollen, apex subacute; ovary and calyx 3–6 mm long, narrow, 6(–10)-ribbed; limb not spreading, (sub)- erect, 2–3 mm long, at margin 2–2.5(–4) mm wide, truncate or inconspicuously toothed; petals 6, inside glabrous, c. 15 mm long; stamens 6, filament 4(–6) mm long, not thickened at base, flattened, hairy at apex and outside, anther c. 10 mm long, connective glabrous; style finely appressed hairy, c. 12 mm long, stigma narrowly conical. Fruit 1 or 2 per infructescence, ripening reddish (purplish?), minutely yellow-greenish hairy, subovoid-ellipsoid, 20–30 mm long, narrowed at base and apex (base not rounded), finely (coarsely) ribbed; calyx remnant short or long (1–) 4 mm high, mostly narrow (limb not spreading), truncate or toothed.

Distribution — Borneo ( Sarawak, Sabah (2 collections), W, C, and E Kalimantan).

Habitat & Ecology — Primary and old secondary lowland mixed dipterocarp forest, often near rivers; yellow, sandy, and red clay soil; from sea level to 300–1000(–1660 (Mikil SAN 41761, Trusmadi FR)) m altitude; flowering and fruiting all year round, but most in October.

Field-notes — Mature fruits dull reddish or dull purple; buttresses and small or large stilt roots recorded.

Vernacular names — Midong (Iban), Ridan (E Kalimantan).

Notes — 1. Alangium mezianum is close to A. borneense , the latter generally with smaller dimensions in most parts, and differing especially in a more conspicuous indument of the curved leaf bud.

2. Alangium mezianum appears to be even in its here conceived restricted sense a variable entity, especially in its general appearance. Beside about 30 collections studied there can be some 10 collections separated as somewhat doubtful as they show traits intermediate with A. borneense , viz. Brunei: Suzuki & Miyamoto K 13266 . – Sarawak: Abang S 48002 , Chai S 34677 , Hansen 918 & 943, Jacobs 5359, Luang S 21882 & S 22478 , Paie S 28242 . – Sabah: Mikil SAN 41761 (in Berhaman (1994) as A. javanicum var. meyeri ) . – E Kalimantan: Church et al. 955 & 2018.