Omalanthus populneus (Geiseler) Pax

A small tree, up to 6(-10) m tall, glabrous and with watery latex; bark greyish and roughened; crown flattish with spreading branches. Leaves triangular-ovate to rhombic-ovate, 3-12 cm x 2.5-10 cm, entire, base of the blade, apex acuminate; blade glaucous beneath, withering yellow to reddish; petiole 2-7 cm long, reddish. Flowers in terminal, 10-25 cm long racemes; male flowers many, with 6-10 stamens; female flowers 2-8 at the base of the raceme, long-stalked, with 2 long stigmas. Fruit a subglobose capsule, ca. 1 cm in diameter, two-lobed, glaucous, with 2 cavaties each containing a single black seed. A.H.L. de Jussieu published the genus as Omalanthus. In the literature, Homalanthus is usually used, but since this is not a conserved genus name, it is incorrect. Omalanthus populifolius Graham is very closely related species from Australia (Queensland, New South Wales). and is rarely found on Woodlark Island and the Louisiade Archipelago. This species is often confused with O. populneus, and sometimes cultivated in botanical gardens. Another closely related species is Omalanthus novoguineensis (Warb.) Lauterb. & K. Schumann, found from the Moluccas, Tanimbar Islands and Timor to the Bismarck Archipelago Solomon Islands and Australia (Queensland). Omalanthus beguinii J.J. Smith is endemic in the Moluccas, and used there in the same way as O. populneus.

It is recorded as growing on various types of soils.

O. populneus is locally common, especially in mountains in secondary forest and young regrowth; it is also found in lowlands in the undergrowth of primary forest and along rivers. It is recorded as growing on various types of soils.

Tannin or dyestuff: The bark and leaves serve in dyeing rattan, matting, pandan handicrafts and cotton cloth black. The rattan, matting and pandan are often buried in the mud before or after being soaked in a boiled infusion of bark and leaves. Medicine: The roots and leaves are used as a medicine, e.g. against fever; the leaves are given to cattle as a vermifuge, but are reported to be poisonous, as is also the latex Sabah for treating wounds, and the terminal buds of about 1 m high plants are reported to be eaten by women to induce abortion. Food: The leaves serve for wrapping taro for cooking. Timber: The wood is sometimes used in houses, but it is soft and not durable.