Castanopsis costata (Blume) A.DC., J. Bot. 1 (1863)

Synonyms
Castanea brevicuspis Miq.
Castanea costata Blume
Castanea spectabilis Miq.
Castanopsis costata var. bancana Scheff.
Castanopsis brevicuspis (Miq.) A.DC.
Castanopsis spectabilis (Miq.) A.DC.
Castanopsis trisperma Scheff.

Diagnostics
Tree with profusely flaking bark. Twigs hairy when young, later glabrous, with many small lenticels. Stipules linear-triangular, large (13 by 1.5 mm). Leaves with widest points near the middle, 17 by 8 cm, lower surface brownish-golden, with many (14-20) secondary veins. Petiole short (1-1.5 cm), distinctly swollen at base. Fruit completely enclosed by spiny cupule, ca. 2.5 cm, splitting in two parts, spines ca. 4-14 mm long.

Description
Tree, 10-36 m by 15-80 cm diameter; bark yellowish to reddish brown, smooth and peeling off profusely. Branchlets when young densely set with fulvous bundle-hairs, later glabrescent, slender, greyish or blackish brown, with many minute lenticels; terminal bud ovoid, 3-5 by 2-3 mm, scales ovate-acute, 3-4 by 2-3 mm. Stipules linear-triangular, 13 by 1.5 mm. Leaves sometimes thickly coriaceous, (9-)14-17(-25) by (4-)5-8(-10) cm (index (1.7-)2.5(-3.2)), widest at or below the middle to sometimes above; base attenuate-acute or rarely rounded and abruptly acute, apex bluntly acute or sharply 0.5-l cm acuminate; above glabrous or sometimes on and near the midrib with a few hairs, glossy olive-green, underneath dull brown with a dense cover of stellate scales (magnification 60!), sometimes also roughish with 2-3-fid bundle-hairs; midrib and nerves strongly prominent beneath, slightly so above; nerves (14-)16-17(-20) pairs, ascending, at an angle of 50-70 degree angle, parallel, arcuating and disappearing towards the margin; reticulation fine, dense, scalariform, obscure on both surfaces; petiole (0.5-)1-1.5(-2) cm, adaxially flat. Male rachis 5-15 cm, 1-2 mm diameter; bracts and bracteoles ovate-acute, 1-1.5 by 1 mm; male flowers solitary or in clusters of 3-7, perianth lobes rounded or acute, membranous, 0.7-1 mm long, densely tomentose; filaments 2-3 mm, anthers 0.2-0.25 mm long; pistillode 0.75-l.5 mm - Female rachis 10-20 cm, 2-3 mm diameter, bracts and bracteoles broadly ovate-acute, thick-coriaceous, 1-1.5 by 1 mm; female flowers in clusters of 3; perianth lobes acute, 0.75-l mm long, densely hairy outside; staminodes 10-12, exceeding the perianth; styles 3, conical-cylindrical, recurved, 1-1.5 mm. Young infructescence up to 20 cm; young cupules numerous, subsessile, obovoid-globose; the segments between the 4 sutures covered with spines. Ripe (?) cupule subsessile to 7 mm stalked, ovoid-globose, 2.5-3 by 3-4 cm; wall 1-2 mm thick, outside densely fulvous hairy, and more or less densely set with bundles of spines 4-14 mm long, fulvous-puberulous except the top, sturdy and more or less recurved or sometimes the inner ones of a bundle slender and straight; inside of wall with dense yellowish brown, silky tomentum. Fruits 1-3 per cupule, more or less conical, 1.5-2 by 1-1.5 cm, the scar covering 0.25 part, convex; the free part with dense yellowish brown silky tomentum; wall thin. [from Flora Malesiana]

Ecology
In undisturbed to slightly disturbed mixed dipterocarp and sub-montane forests up to 1900 m altitude. Quite often along rivers, but also common on hillsides and ridges on sandy to clay soils.

Uses
The timber is locally used for house-building. The nuts are edible.

Distribution
Peninsular Malaysia, Sumatra, Java, Borneo.

Local names
Borneo: Bangan, Berengan, Tibung.