Alangium pallens 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

16. Alangium pallens W.J.de Wilde & Duyfjes , sp. nov. — Fig. 6

Differs from resembling A. ebenaceum in leaves drying greenish brown below and corolla sparsely minutely hairy (leaves drying purplish below and corolla densely hairy in A. ebenaceum ) and from resembling A. meyerii in pale twigs contrasting with blackish brown peduncles (twigs and petioles brown in A. meyeri ). — Type: Kostermans 21328 (holo L L0521448 ; iso A n.v., BO, CANB n.v., G n.v., K K000271862 , NY n.v., P P00542866 , SAR n.v., SING, US n.v.), E Kalimantan , Berau, Mt Njapa on Kelai River, 100 m alt., 17 Oct. 1963, fr .

Etymology. The specific epithet pallens (Latin = pale) refers to the pale brown or whitish twigs.

Tree 10–35 m tall; twigs pale brown or whitish, contrasting with blackish drying colour of petioles and peduncles, 2–5 mm diam, glabrous, sometimes ± angular; leaf bud pale brownish hairy, hairs short or long, 0.1–0.3(‒0.5) long. Leaves: petiole drying blackish, 0.6–2 cm long; lamina drying (greenish) brown, glabrous, elliptic or oblong, 10–23 by 4–9 cm, base subsymmetric, rounded or cuneate, apex acute-acuminate; veins pinnate, 8–18 on each side, occasionally loop-veined; tertiary venation faintly scalariform. Inflorescences (sub)glabrous, drying blackish, of 1 or 2 main branches (peduncles) from the leaf axil, each few-branched, 1–4(–6)-flowered; peduncle (s) 5–15 mm long. Flowers (sparingly) minutely stellate hairy; pedicel 1.5–3 mm long; corolla in bud 10–13 mm long, not swollen at base, apex bluntish or (sub)acute; ovary and calyx 3–4 mm long, ± not ribbed; limb broadly saucer-shaped, c. 1.5 mm long, margin 4–5 mm wide, not or hardly lobed; petals 5, inside sparingly hairy, 12–15 mm long; stamens 5, filament 1.5–3 mm long, inside near apex thickened and hairy, anther 8–10 mm long, connective glabrous; style (sparingly) hairy, c. 10 mm long, stigma blunt-conical. Fruit 1–3 per infructescence, ripening (pink or) red, drying blackish, glabrous, ± flattish, ovoid-ellipsoid, 20–32 by 13–20 mm, smooth or thinly multi-lined; calyx remnant small, narrow.

Distribution — (West) Sumatra, Peninsular Malaysia (Pahang, Terengganu), Borneo ( Sarawak, Sabah, E Kalimantan).

Habitat & Ecology — Primary and secondary forest, on river banks, sand stone rocks; brownish sandy soil, sandstone, and limestone; from sea level to 700 m altitude; flowering in March, May, June, October; fruiting in March, May, July, August, December.

Field-notes — Strongly fluted trunk and buttresses recorded; fruit ripening pink-red or wine-red.

Vernacular names — Kondolon (Dusun), Ladjik (E Kalimantan (Sangkulirang)).

Proposed IUCN (2012) conservation assessment — Least

Concern (LC).

Additional specimens studied. SUMATRA, LaumonierTFB 4530, Sebelah Nature Reserve, 600 m alt., 23 May 1983, fr.; Laumonier TFB 4564, ditto, fr. – PENINSULAR MALAYSIA, Whitmore FRI 8573, Pahang,Sungai Tembeling, 5 m alt., 6 Mar. 1968, fl.; Whitmore FRI 4391, Kelantan, Sungai Lebir Kechil, 160 m alt., 17 Sept.1967, fl. – SARAWAK, Lee S 44284 , 2nd Div., Gunong Lesong, 450 m alt., 3 Dec.1981, fr. – SABAH, Lantoh SAN 83186, Kinabatangan,Sungai Inarat, 700 m alt., 12 May 1976, fl.; Minjulu SAN 77013, Kunak, Madai, 13 Aug. 1973, fr.; Mariyoh et al. SAN 128850, Lahad Datu, Danum Valley, 11 June 1990, fr.; Ampuria SAN 36521, Kinabatangan, Bolungun Hill, 40 m alt., 3 June 1963; Gibot SAN 37144, Tawau, Meretai Besar, 230 m alt., 29 July 1963, fr.; Madani SAN 90138, Kunak, Tingkayu Forest Reserve, 100 m alt., 14 Mar. 1979, fl.; Amin et al. SAN 107114, Tongod, Sungai Pinangah, 13 Oct. 1984, fl.; Kumin SAN 107985, Kinabatangan, Meliau, 20 Oct. 1986, fl.; Meijer SAN 141552, Sandakan, Sepilok Forest Reserve, 18 Aug. 1994, st.; Campbell 204, Lahad Datu, Palum Tambun Nature Trail, 1 July 1991, fr. – KALIMANTAN, Kostermans 13256, East Kalimantan, Sangkulirang, Mt Medadem, 199 m alt., 30 July 1957, fr.

Notes — 1. Stout specimens may be confounded with Alangium ebenaceum , the latter differing in leaves purplish below on drying.

2. Some specimens here included in A. pallens are cited under A. javanicum var. meyeri by Berhaman (1994).

Figures

Fig. 6 Alangium pallens W.J.de Wilde & Duyfjes.a. Flowering twig;b.portion of inflorescence with mature buds;c. stamen seen from the inside;d. flower,corolla and stamens, except one, removed; e. infructescence with one fruit (a‒d: Mariyoh et al. SAN 128850; e: Minjulu SAN 77013, all L). — Drawn by Jan van Os.