Mallotus sumatranus (Miq.) Airy Shaw

Small trees up to ca. 12 m tall and 30 cm dbh, reproductive from 6 m tall and 15 cm dbh. Twigs solid, sparse to densely hairy (short simple, tufted and stellate hairs). Stipules triangular, usually early-caducous, erect, 1-4 mm long by 0.5-1.5 mm wide. Petioles sparse to densely hairy, opposite leaves differing in petiole length, short petioles up to ca. 2 cm long, long petioles up to ca. 6 cm long. Leaves opposite to rarely slightly alternate, opposite leaves differing in size only, ovate, 10.5-20 cm long by 4-8 cm wide, length/width-ratio 2.1-4.38; secondary veins 5-12, not ending in the margin (fading to looping); leaf base obtuse to rounded, slightly cordate; leaf margin with glands, slightly serrate; leaf upper surface glabrous to sparsely hairy on veins, sparsely to numerously gland dotted, with 2-8 basal nectary glands on basal tertiary veins, often basal nectary glands continuing along the whole leaf margin, apical nectary glands usually present; leaf lower surface glabrous to hairy on veins, densely gland dotted, with hair tuft domatia in axils of secondary veins. Staminate inflorescences not branched; flowers clustered per bracteole; bracteoles with entire margin. Pistillate inflorescences not branched; fruits up to ca. 6 cm in diameter (including wings), 3-locular, without spines but with each carpel with long horizontal spine-like appendage.

Ecology: Collected up to ca. 50 m altitude. A shade tolerant forest understorey species, restricted to swamp forests.

Distribution: Sumatra and Borneo. In Borneo collected in West-, Central- and East-Kalimantan.