Tree 10-35 m. Leaves chartaceous, oblong (-lanceolate), 7-14 by 2.5-6 cm, base attenuate, apex rounded, obtuse, or bluntly short-acute-acuminate, upper surface brown to blackish on drying, sometimes with few minute whitish dots or pustules; Inflorescences glabrescent or with sparse hairs 0.1-0.2 mm, short and stout, 2 or 3 times branched, peduncle 0.1-1 cm long, rather many-flowered; Fruits 2-6 per infructescence, ellipsoid, 1-1.6 by 0.8-1.2 cm, apex minutely pointed, base subattenuate, glabrous, without or with sparse small tubercles or lenticels;
Asia-Tropical: New Guinea present, Digul present, Papua Barat present, Papua New Guinea present, Western Prov present
Malesia: New Guinea (Papua Barat, Digul; Papua New Guinea, Western Prov.).
Apparently related to H. sepikensis, one of the few other New Guinean species with 3-lobed perianths. That species differs in non-angular twig apices, more elongate perianth, more slender inflorescences, membranous leaves, and apparently a different ecology. Horsfieldia olens is mostly found in dry or wet habitats on poor peaty or podzolic soils.