Dipterocarpus hasseltii Bl., Fl. Jav. 2 (1829)

Named after J.C. van Hasselt [1797-1823], a Dutch physician and zoologist in Java.

Dipterocarpus basalmiferus Bl.
Dipterocarpus lampongus Scheff.
Dipterocarpus pentagonus DC
Dipterocarpus quinquegonus Bl.
Dipterocarpus subalpinus Foxw.
Dipterocarpus tampurau Korth.
Dipterocarpus trinervis (non Bl.) Foxw.

Upper canopy tree up to 45 m tall and 126 cm dbh. Stem with resin. Stipules up to ca. 120 mm long. Leaves alternate, simple, penni-veined, glabrous, lamina folded between secondary veins. Flowers ca. 30 mm in diameter, yellow-pinkish?, placed in unbranched inflorescence. Fruits ca. 30 mm long, green-red, with two ca. 190 mm long wings placed on top of the nut, wind dispersed.

Parts of petals expanded in bud and ovary apex densely persistently buff puberulent, calyx at first frequently so, nerves beneath sparsely so or glabrescent, otherwise glabrous. Twig c. 4 by 2 mm apically, somewhat compressed, black. Buds to 20 by 5 mm, falcate-lanceolate, drying black; stipules to 12 by 1 cm, lorate-lanceolate, subacute. Leaves 9-16 by 5-10 cm, elliptic, subcoriaceous, prominently plicate; margin +/- prominently crenate; basecuneate; acumen to 1 cm long, short; nerves 11-14 pairs, slender but prominent beneath, ascending: petioles 2.5 cm long, slender. Inflorescences to 10 cm long, axillary, bearing to 4 +/- secund flowers. Flower buds to 3 by 1 cm, fusiform. Stamens 30, shorter than style at anthesis; filaments c. half the length of anthers, long, broad and compressed at base, rapidly tapering and filiform above; anthers linear, somewhat tapering distally; appendage acicular, very slender, c. 0.66 length of anther. Ovary narrowly ovoid-lanceolate, tapering into the very long slender filiform style; gynoecium puberulent except for the distal quarter. Fruit pedicel to 3 by 2 mm; calyx tube to 3 cm diameter, subglobose smooth; 2 longer lobes to 22 by 3 cm, lorate-spatulate, usually obtuse. 3-nerved, c. 9 mm wide at base; 3 shorter lobes to 15 by 13 mm, suborbicular, subrevolute, prominent. [from Flora Malesiana]

Lowland dipterocarp forests on well-drained but moist fertile red soils in valleys and on hillsides, sometimes on calcareous soil, even limestone (Java); sometimes gregarious; to 600 m elevation.

Timber is commercially harvested.

Peninsular Thailand, Peninsular Malaysia, Sumatra, Java, Lesser Sunda Islands, Borneo, Philippines.

Local names
Borneo: Beo, Kaladan, Keladan, Keruing, Keruwing, Tempuran.