Macaranga hosei King ex Hook.f., Fl. Brit. India 5: 449 (1887)

Synonyms
Macaranga pseudopruinosa Pax & K.Hoffm. in Engl.

Diagnostics
Tree up to ca. 30 m tall and 45cm dbh, reproductive from 4 m tall and 5 cm dbh. Twigs starting out solid, after ant colonization (usually in sapling stage) hollow, glabrous, sometimes glaucous, with small ant openings (ca. 1 mm diameter). Stipules (broad ovate to) rounded, persistent, usually perpendicular to the twig, usually (almost) completely surrounding the twig, 9-21 mm long by 10-20 mm wide. Petioles glabrous, up to ca. 30 cm long. Leaves alternate, usually not peltate, 3-lobed, 10-24 cm long by 14-34 cm wide, length/width-ratio 0.65-0.82; secondary veins 7-18, ending in the margin; central lobe 4.5-16 cm long by 5.5-12 cm wide, lateral lobes 3.5-13 cm long; leaf base broadly cordate (usually also when peltate), peltate margin length (when present) 0.3-1.8 cm; leaf margin with glands; leaf upper surface glabrous; leaf lower surface usually densely hairy (short simple hairs), densely gland dotted. Staminate inflorescences branched; flowers clustered per bracteole; bracteoles with fimbriate margin; Pistillate inflorescences branched; fruits 5-6 mm wide, 2-locular, covered with yellow sticky glandular exudates.

Description
Large tree with a bluish-green appearance, to 20-30 m tall and 30-40 cm dbh, although flowering somewhat smaller; twigs 6-11 mm in diam., terete, glabrous, usually densely glaucous. Bark pale grey, white or light brown, prominently hoop-marked, smooth or minutely fissured. Stipules 10-15 by 10-15 mm, orbicular surrounding the stem, erect and perpendicular to the stem, many pairs persistent, coriaceous, not succulent, glabrous, producing food bodies on the adaxial surface. Leaves: petioles terete, slender, 10-25 cm long, slightly glaucous, glabrous; blades broader than long to almost rounded, not flat, slightly convex, 8-20 by 10-25 cm, deeply trilobed, dissected to c. 1/2-3/4, the lateral lobes almost the same size as the central lobe, the lateral lobes slightly asymmetrical, not peltate or rarely 1-5 mm peltate, base very broadly rounded, strongly cordate, margin +/- entire with small conical nectaries along the basal margin and usually along all margins, the distal margin sometimes appearing wavy to dentate, apices acute or shortly acuminate, 1st degree venation palmate with 5 prominent veins and 2-3 less prominent veins arising from the petiole insertion, 2nd-3rd veins densely scalariform, 4th venation loosely scalariform, minor veins usually prominent and finely reticulate; adaxial surface glabrous, abaxial surface with dense to rarely sparse erect silvery hairs along all veins and densely punctate glandular; young leaves green, adaxial surface glabrous or with a few minute ferrugineus hairs at the petiole insertion, abaxial surface densely covered in silvery erect sharp hairs. Staminate inflorescences erect narrow panicles often extending above the leaves, 20-40 by 10-20 cm, to 4 axis orders, basal unbranched axis strongly flattened and usually more than 1/2 of the total inflorescence length, first pair of secondary branches alternate without accessory branches, basal axes glabrous, distal axes with silvery to ferrugineus pubescence; bracts ovate, 5-7 mm long, margin entire, glabrous, often persistent; flower clusters with 6-15 flowers, spirally arranged on inflorescence branches; bracteoles broadly ovate, 4-6 by 3-4 mm, margin irregularly deeply dentate with spreading narrow unequal teeth, apex broadly acute, both surfaces covered in minute silvery to ferrugineus hairs. Staminate flowers c. 0.7 mm long, yellow-green, shortly pedicellate; sepals 3, free, densely pubescent; stamens 2-3; anthers 4-locular. Pistillate inflorescences erect narrow panicles often extending above the leaves, 15-35 cm long, up to 3 axis orders, basal unbranched axis strongly flattened and usually more than 1/2 of the total inflorescence length, basal axes glabrous, distal axes with silvery to ferrugineus pubescence; bracts ovate, 5-10 mm long, margin entire, glabrous, often persistent. Pistillate flowers c. 1.5 mm long; calyx urceolate, c. 1 mm long, with fine silvery or ferrugineus hairs; ovary 2-carpellate; styles c. 1 mm long, free, persistent. Fruits bilocular, 4-5 by 5-6 mm, green or yellowish-green at maturity, locules subglobose, without processes, covered in yellowish-green, sticky exudate; pedicel slender, 5-8 mm long, with fine silvery or ferrugineus hairs. Seeds c. 3 mm in diam., lenticular, black, shallowly pitted, encased in a fleshy violet aril. [from http://www.nationaalherbarium.nl/Euphorbs/specM/MacarangaT.htm]

Ecology
Common early successional tree in lowland forests throughout west Malesia up to ca. 600 m elevation. It occurs on a wide range of substrates from nutrient-poor sandy soils to richer shale-derived soils, although it seems to be more abundant on the former particularly in Borneo. It can also be found on soils across a wide range of soil water levels. In some areas it occupies the margins of swampy ground, although not usually in swamps, and in other areas it occurs on raised ridges of apparently low soil water status. It is a very high-light demanding pioneer tree and grows quickly in good conditions. It is one of a group of species that grows to be a relatively large tree. It can be found in degraded land, logged forest and in large openings within primary forest where it may persist for approximately 30 years.

Uses

Distribution
Peninsular Thailand and Malaysia, Sumatra and Borneo.

Local names