Alangium oblongum Craib

Dewilde, W. J. J. O. & Duyfjes, B. E. E., 2017, Taxonomy of Alangium section Conostigma (Alangiaceae), Blumea 62 (1), pp. 29-46 : 40-43

15. Alangium oblongum Craib — Fig. 5

Alangium oblongum Craib (1930) 426;(1931) 807. — Type: Kerr 17028 (holo

K K000704837;iso BK,BM BM000944972), Thailand, Ranong, Kampuan,

50 m alt., 6 Feb. 1928, fl. Alangium costatum auct. non (Boerl.) Boerl. ex King: King (1902) 78. Alangium ridleyi auct. non King: Evrard (1923) 1186; Tardieu (1968) 48. Alangium javanicum var. meyeri auct. non (Merr.) Berhaman: Berhaman

(1994) 35, p.p.

Tree 10–30 m tall; twigs brown, 2–4(–5) mm diam, at apex with (dense) minute hairs c. 0.1 mm long, glabrous or early glabrescent; leaf bud straight, with short minute, scale-like hairs c. 0.1 mm long. Leaves: petiole 1.2–1.5 cm long; lamina drying (greenish) brown, glabrous (early glabrescent), elliptic or elliptic-oblong, 12–25(–30) by 4–10 cm, base symmetric, (rounded or) short or long-attenuate, apex acute-acuminate; veins pinnate, 8–15 per side, loop-veined towards apex of lamina; tertiary venation reticulate or thin-scalariform. Inflorescences glabrous (or minutely hairy), of 1–3 main branches (peduncles) from the leaf axil, each few-branched, 1–5(–10)-flowered; peduncle (s) to 10 mm long. Flowers minutely hairy (hairs c. 0.1 mm long); pedicel 2 – 4 mm long; corolla in bud 12(–15) mm long, not swollen at base, apex subobtuse; ovary and calyx 2– 4 mm long, usually 10–12-ribbed; limb ± spreading, 1(–2) mm long, at margin 3.5–4 mm wide, subtruncate with straight or (faintly) lobed margin; petals 6, minutely hairy (appearing as glabrous) inside, 12–15 mm long; stamens 6, filament c. 4 mm long, hairy in upper part, not thickened at base, anther c. 8 mm long, connective glabrous; style hairy, 8–10 mm long, stigma narrowly conical. Fruit 1–3 per infructescence, ripening purplish, (sub)glabrous, ovoid-ellipsoid, 20–30(–35) mm long, usually (irregularly) coarsely bluntly (6–)10–12-ribbed; calyx remnant short, c. 5 mm wide.

Distribution — India (Nicobar Isl.), Myanmar, Thailand, Vietnam; in Malesia: Sumatra (Aceh, Lankat), Peninsular Malaysia (Perlis, Kedah, Terengganu, Selangor), Borneo ( Sarawak, Sabah, Kalimantan, Natuna Isl.).

Habitat & Ecology — Primary forest, mixed dipterocarp forest, dipterocarp forest, flatland, hillside, sandy ridges, and along rivers; yellow clayey soil; 30–700 m altitude; flowering and fruiting all year round.

Uses ― Wood for constructions and canoes.

Field-notes ― Van Balgooy et al. 5357: “fruit purple, 1 seed covered by a white sweet sour juicy carcotesta, edible, favourite food of pigs and primates, very common” and Argent 9615 et al. “tree with bright red edible fruit, brought into camp to be eaten”. Bark whitish or whitish brown; stilt roots and buttresses recorded.

Vernacular names ― Taramajang boeloeh (Aceh), Jadam (Malay), Midong or Midung (Iban), Senumpul, Pangoron (Batak).

Notes — 1. Marlea costata Boerl. was described on material cultivated in the Botanical Garden in Bogor , grown from seed said to be collected by Teijsmann(?) in S Sumatra. This material (in L) is at present relegated to A. javanicum .

2. It could be imagined that three here accepted species, viz. A. oblongum , A. meyeri , and A. ridleyi are exponents of one single species, only differing in sizes and in facies, as there seem to be sufficient intermediates to connect them. However, we do not believe this, as it readily appears incredible to unite e.g. ‘typical’ A. ridleyi from Singapore, a plant with robust twigs, with A. meyeri , a plant of much more delicate stature, from Luzon. On the other hand, also A. javanicum (a species with obvious hairy leaf bud, and small fruits, 15–20 mm long), seems to intergrade with A. meyeri , typically with an indument of minute scale-like hairs. In this way, the ‘ javanicum complex’ problem, as alluded to in the introduction, is replaced by a smaller ‘ oblongum complex’ problem which again needs further study; probably some more not yet defined taxa are involved.

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

Figures

Fig. 5 Alangium oblongum Craib. a. Portion of flowering branch; b. inflorescence; c. flower bud; d. flower at anthesis showing ovary, calyx limb, disc, style, and conical stigma (petals and stamens removed, except one of each); e. stamen; f. fruit (a–d: Wongprasert s.n. (SN130168); e: Suddee et al. 3509, BKF; f: Poilane 10950 (Annam), L). — Drawn by Jan van Os.