Hopea odorata Roxb., Pl. Coromandel 3: 7 (1811)

Synonyms
Hopea decandra Buch.-Ham. ex Wight
Hopea vasta Wall. [Invalid]
Hopea wightiana Miq. ex Dyer [Invalid]
Neisandra indica Raf.

Diagnostics
A large tree reaching up to 45 m in height with the base of the trunk reaching a diameter of 4.5 m (including buttresses). Stipules present but minute and dropped early. Leaves alternate, with clear secondary venation and conspicuous domatia along the midrib on leaf lower surface. With small yellow-white flowers, with spiraly overlapping petals. Fruits with two long wings (ca. 5 cm) and three short ones (ca. 0.5 cm). Nut ca. 6 mm.

Description
Tall buttressed tree with dark brown flaky bark. Twig apices sparsely fugaceous pale buff puberulent; panicle, leaf buds, flower calyx and petals outside densely persistently so; fruit calyx lobes and frequently nut glabrescent. Twig c. 2 mm apically, terete, dark brown, smooth to rugulose; stipule scars pale, minute. Buds minute, ovoid; stipules minute, fugaceous. Leaves 7-14 by 3-7 cm. ovate- lanceolate, falcate; base broadly cuneate, unequal; acumen to 1.5 cm long, broad; nerves 9-12 pairs, prominent beneath, narrowly depressed above, arched, with prominent porous saccate axillary domatia; tertiary nerves densely sinuate-scalariform, very slender but clearly evident on both surfaces; midrib prominent beneath, applanate to somewhat channelled above; petiole 10-16 mm long, slender. Panicle to 12 cm long, terminal or axillary, twice-branched, with many to 2.5 cm long branchlets bearing to 9 secund flowers. Flower buds to 3 by 2 mm, broadly ovoid. Outer 2 sepals lanceolate, obtuse or subacuminate; inner 3 broadly ovate, acute. Petals pale cream-yellow. Stamens 15; filaments slender, compressed at base, tapering; appendage slender, as long as narrowly ellipsoid anthers. Ovary ovoid, punctate or glabrous, surmounted by an equally tall columnar style. Fruit pedicel to 1 mm long, short, slender, 2 longer calyx lobes to 5.5 by 2 cm, +/- broadly spatulate, obtuse, c. 3 mm broad above the to 4 by 4 mm small elliptic saccate base; 3 shorter lobes to 4 by 4 mm, ovate, subacuminate. Nut to 6 by 5 mm, small, ovoid, subobtuse. [from Flora Malesiana]

Ecology
Often gregarious along river banks, up to 600 m elavation.

Uses
Timber is used. Also cultivated as a shade tree. In Thailand this tree is believed to be inhabited by a certain tree spirit known as Lady Ta-khian. Durable timber used for shipbuilding and houses. Bark is rich in tannins and used to treat diarrhoea, and sometimes used to replace betel nut in betel quid. It is one ingredient of a remedy for the treatment of inflammation of the gums and incontinence. Resin of the trunk is a popular styptic and is used as an ointment for wounds and sores.

Distribution
From Bangladesh into Indochina and Peninsular Malaysia.

Local names
Bengali: Telsur, Teksol, Tersol.
Burmese: Thingan net, Sauchi.
English: White thingan, Rock dammar.
Lao (Sino-Tibetan): Kh'e:n. Malaysia: Chengal pasir, Chengal kampong, Chengal pulau, Chengal mas, Merawan siput jantan.
Thailand: Ta-khian, Takhian-yai, Takhian-thong. Vietnamese: Sao den, Koki mosau.