Tree c. 20 m. Leaves membranous, (elliptic-)oblong, 10-15 by 4-7 cm, base short-attenuate, apex short acute-acuminate; Inflorescences behind the leaves, with ± sparse hairs 0.1 mm; Fruits (of S 36305, see note 2) 2 or 3 in a short, stout infructescence, broadly ellipsoid, 5-5.5 by 3.5-4 cm, glabrous, with a few, small tubercles, pericarp 7-10 mm thick, perianth not persistent.
Asia-Tropical: Borneo present (Sarawak present); Philippines (Philippines present), E Kalimantan present, Palawan present
Malesia: Borneo (E Kalimantan, possibly Sarawak, see note 2), Philippines (Palawan).
1 Horsfieldia obscura keys out beside H. subalpina (accepted for Borneo as subsp. kinabaluensis and restricted to the montane forest in the Kinabalu area). The latter differs from H. obscura in the more elongate male buds, cleft to nearly halfway, short-ellipsoid androecium, more rigid leaves, and smaller fruits with less thick pericarp. Horsfieldia obscura appears to be closely related to typical H. subalpina, from Peninsular Malaysia, which differs in habit (larger leaves, more distinct lenticels on twigs, larger inflorescences), in male flowers cleft to about halfway, and smaller fruits. 2 Some doubtful specimens in fruit, all from Borneo, key out beside H. subalpina, H. obscura, or H. discolor. These specimens are discussed by De Wilde (I.e.), and may represent new species.