Lithocarpus lucidus (Roxb.) Rehder, J. Arnold Arbor. 1: 128 (1919)

Synonyms
Cyclobalanus omalokos (Korth.) Oerst.
Lithocarpus omalokos (Korth.) Rehder
Pasania lucida (Roxb.) Gamble
Pasania omalokos (Korth.) Schottky
Quercus cuneata Roxb. ex Wall. [Invalid]
Quercus hasseltii Korth. ex Miq.
Quercus lucida Roxb.
Quercus omalokos Korth.
Synaedrys lucida (Roxb.) Koidz.
Synaedrys omalokos (Korth.) Koidz.

Diagnostics
Large trees up to ca. 50 m tall and 120 cm diameter. Stipules present. Leaves alternate with short petiole, leaf blade fleshy, elliptic-obovate, hairless, pinnately veined with many inconspicuous secondary veins, margins curved downward, tip rounded, upper surface shiny. Male inflorescences in spikes of up to 20 cm long, female inflorescences slightly shorter. Fruit a nut with a diameter of ca. 3 cm that is less than half covered by the cupule. Cupule with spiral ridges.

Description
Tree up to 50 m tall, 120 cm diameter; buttresses up to 1 m tall. Bark smooth, brown; inner bark granular, yellowish brown. Sapwood yellowish to brownish. Twigs glabrescent, sparsely lenticellate. Stipules linear, 2-3 x 1 mm. Leaves coriaceous, sometimes rigid, glabrous on both surfaces, shining above; oblanceolate, (4-)8-12(-16) x (2-)4-6(-8) cm, base cuneate, decurrent, margin revolute sometimes undulate, apex rounded, obtuse, acute to abruptly cuspidate; midrib faintly raised on both surfaces; lateral veins thin, (10-)14-16(-20) pairs, dense, flat on both surfaces or slightly raised below, faintly joining near the leaf margin, forming an angle of 40-60 degrees with the midrib; intercostal venation reticulate, dense, thin but distinct on both surfaces; petiole 2-7 mm long. Inflorescences male, female or androgynous. Male inflorescences 9-20 cm long; bracts and bracteoles ovate, 0.6-1 x 0.3-0.6 mm. Male flowers in clusters of 3-4 along the rachis; perianth lobes obtuse, c. 1 x 0.8 mm; stamen filaments c. 2 mm long; pistillode globose, c. 0.8 mm diameter. Female or androgynous inflorescences 10-20 cm long; bracts narrowly ovate, c. 1.4 x 0.3-0.6 mm; bracteoles broadly ovate, c. 1 x 0.9 mm. Female flowers solitary or in clusters of 3 along the rachis; perianth lobes acute, c. 1 x 0.7 mm; staminodes 10; styles conical, straight, c. 1.2 mm long. Cupules solitary but arranged closely together or sometimes in clusters of 3 along the rachis, sessile or with stalk c. 5 mm long, cupor saucer-shaped, 0.5-1(-1.5) x 2-3.5 cm, glabrescent, lamellate; wall woody, thick, glabrescent, enclosing half or less of the acorn; lamellae dense and distinct, edge minutely denticulate or undulate, set in 8-11 regular lines. Acorns depressed ovoid, 1.5-2.5 x 2-3.5 cm, most part exserted, glabrous and shining, brown purplish; base flat, apex rounded or acute; scar deeply concave 1.5-2 cm diameter; wall woody, thin, most part free from the cupule. [from Tree Flora of Sabah and Sarawak]

Ecology
In primary hill mixed dipterocarp forest to lower montane forest, up to 1400 m altitude, on clay, sandy-clay and sandstone-derived soils.

Uses
The wood is locally used for house construction.

Distribution
Sumatra, Peninsular Malaysia and Borneo.

Local names
Borneo: Sarusup tembaung (Dusun, Kimanis), Saled arong (Kelabit).