Quercus gaharuensis Soepadmo

Borneo, Sumatra, Malaysia; 100-1400 m;

reaches 30 m, with trunk to 1 m in diameter;

6-20 cm x 3-6; thin-coriaceous; lanceolate to oblong or elliptic; apex rounded or bluntly acute ; base attenuate, acute or seldom rounded, slightly asymmetrical; margin plane remotely serrulate near apex; hairless above; beneath sparcely tomentose with brownish stellate hairs, more or less glabrescent; 8-15 pairs of secondary veins, parallel, forming an angle of 45-60° with the midrib; tertiary veins distinct below; pétiole 1-3 cm long, densely tomentose at first, then glabrescent;

male catkins to 3.5 cm, hairy; male flowers in clusters of 3, with 4-5-lobed, hairy perianth, 4-6 stamens, pistillode replaced by tufts of stiff hairs. Female inflorescences to 1.5 cm, 2-4-flowered, with 5-6-lobed perianth, 3-4 styles 1-2 mm long, without staminodes;

acorn conical 2-3 cm long, 2 cm wide, densely tomentose at first, then glabrescent, with apex obtuse and base flat or convex; cupule 2 cm in diameter, enclosing almost all the fruit, with 6-8 denticulate rings; maturing between September and February;

not hardy;

– Sub-genus Cerris, Section Cyclobalanopsis; – Section Helferiana, sub-section Subpedicellatae ( Menitsky ); – Threatened (IUCN Red List Category : VU).