Anisoptera costata Korth., Kruidk. (1841)

Latin for 'with clear venation'.

Synonyms
Anisoptera cochinchinensis Pierre
Anisoptera glabra (non Kurz) Pierre
Anisoptera marginatoides Heim.
Anisoptera mindanensis Foxw.
Anisoptera oblonga Dyer
Anisoptera robusta Pierre
Dipterocarpus parallelus Korth. ex Burck
Dryobalanops hallii Korth.
Shorea nervosa Kurz

Description
Emergent tree up to 67 m tall and 152 cm dbh. Stem with resin. Twig of variable thickness, at first frequently angular, becoming minutely striated or smooth, terete. Bud 3-5 by 1.5-3 mm, ovoid, somewhat compressed, acute. Stipule c. 8 by 3 mm, hastate, acute, fugaceous. Leaves 6-18 by 7-11 cm, thinly coriaceous, frequently slightly bullate, oblong to obovate, undersurface grey-green lepidote to golden or chocolate; base obtuse or broadly cuneate; acumen to 5 mm long; margin not revolute or only slightly so; nerves 8-22 pairs, at 60-70 degrees; petiole 2-4 cm long. Panicle to 20 cm long, terminal or axillary, angular, pendent, doubly or trebly branched, branchiets bearing up to 5 flowers; bracteoles to 4 by 2 mm, hastate, acute, shortly densely pubescent. Flower bud to 12 by 6 mm, ovoid, acute. Calyx densely tomentose outside, shortly pubescent within; lobes deltoid, ca. acute, acuminate, of varying lengths. Corolla cream; petals broadly hastate, acute, shortly puberulent on parts exposed in bud. Stamens c. 25 (to 35 outside Malesia), subequal; filaments short, compressed; anther oblong, tapering apically; appendage to connective about twice as long as anther, filiform, tapering, reaching, almost to apex of stylopodium. Stylopodium cylindrical, somewhat tapering, densely pubescent; style short, trifid, pubescent at base, otherwise glabrous. Fruit calyx shortly pubescent, tube glabrescent; tube to 1 by 1.2 cm, globose, tapering gradually to the pedicel, narrowed to 8 mm at the neck; 2 longer calyx lobes to 16 by 1.5-2 cm, spatulate, obtuse, c. 5 mm broad at base; 3 shorter lobes to 20 by 4 mm, variable, hastate, base slightly constricted. Nut apex broadly conical, crowned by a c. 2.5 by 1.5 mm oblong stylopodium, shortly pubescent. [from Flora Malesiana]

Ecology
Common, often gregarious, in Semi-evergreen Dipterocarp forest and evergreen forest in seasonal areas; rare but widespread in lowland forest in everwet areas, up to 700 m elevation. Usually growing on ridges with sandy to clayey soils, sometimes along rivers. Occasionally found on limestone.

Uses
Plywood.

Distribution
Indo-China, Birma, Thailand, Peninsular Malaysia, Sumatra, Java, Borneo, Philippines.

Local names
Borneo: Baripung, Damar ketimpun, Damar tingkis, Katimpun, Kenuar, Laripung, Merlangat, Mersawa, Pengiran, Tempudau.
Malaysia: Mersawa, Mersawa kesat, Mersawa terbak, terbak, meranti terbak, pokok pahit.
Sumatra: Masegar, tenan, meluwang tikus.