e-flora of Sabah and Sarawak Acer laurinum

 Acer laurinum Hassk. 

(Latin, laurinum = resembling Laurus; the blue-grey colour of the leaves)


Medium-sized to large tree up to 50 m tall; clear bole straight, cylindrical, up to 28 m tall and 70 cm diameter; buttresses about 1.5 m high and 2 m out, thin, spreading, slightly concave; crown dense, pale fresh green from below, more or less conical to hemispherical, deciduous to semi-evergreen. 

Bark initially smooth, greenish grey, becoming rich red to grey-brown and longitudinally fissured and flaky with age; inner bark c. 1.5 cm thick, firmly fibrous, yellow-brown to red-brown, somewhat mottled, sometimes laminated. Heartwood absent; sapwood white to pale yellow, with rather distinct concentric growth rings. Twigs slender, terete or ribbed, drying nearly black, with numerous leaf-scars and minute lenticels. Buds numerous, c. 4 mm long, covered by 4–11 pairs of decussate, caducous scales of c. 2 mm long. 

Leaves thinly leathery, glabrous, elliptic to ovate-lanceolate, 7–23 x 3–6 cm, glaucous to grey beneath, upper surface dark green when fresh, drying dull red-brown; base rounded to obtuse, margin entire, apex acute to acuminate-caudate; midrib slender, slightly raised above, more or less prominent beneath; lateral veins 4–9 pairs, very slender, with a pair at the base of the midrib; intercostal veins fine, reticulate; stalk 2–7.5 cm long, slender. 

Inflorescences in the axils of fallen leaves, paniculate or corymbose, 3–10 cm long, 30–50-flowered; bracts and bracteoles fairly well-developed. Male flowers: sepals and petals (3–)5, free, obliquely erect, respectively 2.5–3 and 1.5–2.5 mm long; stamens (4–)6(–8), arranged in one whorl on a flat, glabrous to woolly disc, filaments c. 5 mm long, anthers c. 1 mm long; pistillode strongly reduced. Female flowers with sepals and petals as in the males; staminodes strongly reduced; ovary densely hairy, c. 2 mm across; styles 2, c. 1.5 mm long, stigmas 2, sessile. Fruits red, wings 4–7.5 x 1–2.5 cm, asymmetrical, narrowed towards the base, pubescent. Young seedling leaves coarsely and distantly toothed; sapling leaves whorled.

Vernacular name. Sarawak—perdu (Malay).

Distribution. Burma, possibly Thailand, Sumatra, Peninsular Malaysia, Java, Borneo, the Phillipines, Celebes and Lesser Sunda Islands. Rare in truly non-seasonal parts of Peninsular Malaysia, Sumatra and Borneo, but relatively common elsewhere. In Sabah uncommon, known only from 2 collections from Mt. Kinabalu (SAN 38438) and Nabawan (SAN 124720). In Sarawak, it has a very local distribution, but is frequent where it occurs, e.g., in the Hose Mts. (3rd Div.), Mt. Meluku (2nd Div.), and Usun Apau Highlands (4th Div.). Ecology. Apparently confined to soils of relatively high nutrient status, on igneous rocks at 200–1500 m in the upper limits of Mixed Dipterocarp Forest and on granodiorite rocks in the oak-laurel lower montane forests around 1200–1600 m. Flowering has been recorded in April–August and fruiting in July–November. In Sabah, fruiting has been rarely recorded.

Location: Borneo

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