Alangium ledermannii 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 : 35

9. Alangium ledermannii W.J.de Wilde & Duyfjes , sp. nov.

Differs from resembling A.hollrungii in twigs, inflorescences and flowers hairy (glabrous in A. hollrungii ), thicker twigs,c. 0.5 mm (c. 0.3 mm in A. hollrungii ). — Type: Ledermann 9818 (holo L L.2497874; iso B †), Papua New Guinea, April River, 200–400 m alt., 22 Nov. 1912, fl .

Alangium meyeri auct. non Merr.: Melch. & Mansf., Bot. Jahrb. Syst. 60 (1925) 163.

Etymology. The specific epithet refers to the Swiss botanist Carl Ludwig Ledermann,who in 1912/13 joined an expedition along the Empress Augusta River (Sepik River).

Small or medium tree, 4 –20 m tall; twigs dark grey-brown, c. 5 mm diam, glabrescent from scurfy hairs c. 0.3 mm long; leaf bud not seen. Leaves: petiole 1(–1.4) mm long; lamina drying greenish brown, glabrous, elliptic, 9–12 by 4.5–7 cm, base slightly asymmetric, (broadly) rounded, apex short acute-acuminate; veins pinnate, 8–12 on each side; tertiary venation finely scalariform-reticulate. Inflorescences densely finely hairy (hairs 0.2–0.3 mm long), of 1 or 2 main branches (peduncles) from the leaf axils, 4–20-flowered; peduncle (s) 4–8 mm long. Flowers (submature buds) densely scurfy hairy; pedicel 1–2 mm long; corolla in bud 8–9 mm long, base not swollen, apex acute; ovary and calyx c. 4 mm long, limb c. 1 mm long, at margin 2.5–3 mm wide, not or hardly lobed; petals 6, inside almost glabrous, c. 10 mm long; stamens 6; filament c. 1 mm long, glabrous, not thickened, anther c. 6 mm long, connective glabrous; style densely hairy, c. 4 mm long, stigma (short) conical. Fruit not known.

Distribution — Papua New Guinea (East Sepik).

Habitat & Ecology — Dense, moist primary rain forest with ferns and mosses; 200–400 m altitude; flowering in November.

Proposed IUCN (2012) conservation assessment — Data Deficient (DD), although there is concern as the species has been collected only twice.

Note — Alangium ledermannii is only known from two collections from Sepik area: Ledermann 9818, the type, and Ledermann 9795, collected between 1912 and 1913 .