Alangium plumbeum W.J.de Wilde & Duyfjes, 2017

Dewilde, W. J. J. O. & Duyfjes, B. E. E., 2017, Taxonomy of Alangium section Conostigma (Alangiaceae), Blumea 62 (1), pp. 29-46 : 43

17. Alangium plumbeum W.J.de Wilde & Duyfjes , sp. nov.

Most similar to A. hollrungii but differing in hairy filaments and hairy petals within (filaments glabrous and petals glabrous within in A. hollrungii ). — Type: Gafui et al. BSIP 8666 (holo L L.2497913; iso BSIP), Solomon Isl., N Kolombangara, 18 Jan. 1968 .

Etymology. The specific epithet plumbeum (Latin = leaden grey) refers to the drying colour of the leaves.

Tree 6– 20 m tall; twigs pale brown or grey, 1–3 mm diam, glabrous (early glabrescent from hairs 0.1 mm long or less); leaf bud densely grey-brown hairy (hairs c. 0.1 mm long). Leaves: petiole 0.5–1 cm long; lamina drying blackish brown with a leaden grey tinge, glabrous, elliptic, 9 –16 by 4 –7 cm, base symmetric, cuneate or rounded, apex acute-acuminate; veins pinnate, 5 or 6 on each side; tertiary venation thin, reticulate-scalariform. Inflorescences minutely hairy (hairs less than 1 mm long), of 1 (or 2) branches (peduncle(s)) from the leaf axil, each few-branched, with 1–4(–5) flowers; peduncle (s) 2–7 mm long. Flowers hairy as the inflorescences; pedicel 1(–2) mm long; corolla in bud 7–11 mm long, not swollen at base, apex subacute or narrowly rounded; ovary and calyx 3–4 mm long, finely ribbed; limb c. 1.5 mm long, margin c. 3 mm wide, unlobed or minutely toothed; petals 5, inside minutely hairy, 11(–15) mm long; stamens 5, filament 1.5‒3 mm long, broadened (except at apex), inside and at apex hairy, outside glabrous or hairy, anther 7‒10 mm long, connective glabrous; style hairy (except towards base), 8–12 mm long, stigma short-conical. Fruit 1 (or 2?) per infructescence, green, drying blackish, minutely sparsely hairy, glabrescent, ellipsoid (slightly narrowed at base and apex), 25–30(–35) by 12–15 mm, smooth; calyx remnant small.

Distribution — Solomon Isl., widespread; in Malesia: Papua New Guinea (Bougainville Isl., only known from Gideon LAE 78669, a sterile specimen).

Habitat & Ecology — Primary & secondary forest, also swamp forest; on sandstone; at low altitudes; flowering April to July; fruiting in November, January and May.

Field-notes — Thin plank-like buttresses; flowers purplewhite or cream.

Proposed IUCN (2012) conservation assessment — Least Concern (LC), as the species is widespread in the Solomon Isl.