Tree 10-20 m. Leaves membranous or chartaceous, elliptic-oblong to oblong-lanceolate, 13-26 by 4-8 cm, apex up to 1.5 cm acute-acuminate, base rounded to attenuate; Inflorescences: Fruits 1-5 per infructescence, broadly ellipsoid, more or less ridged, base rounded, apex subacute, 2-2.7 by 1.5-2 cm, with dense rusty hairs 0.1-0.2 mm long;
Aceh present, Asia-Tropical: Sumatera (Sumatera present), E Coast present, Palembang present
Malesia: Sumatra (Aceh, E Coast, Palembang).
Knema losirensis is related to K. glaucescens, particularly resembling the Sumatran specimens of the latter. These differ in a less stout habit of the leafy twig, with smaller male flowers and smaller fruits. The comparatively large, ridged fruits of K. losirensis are quite different from the fruits of K. glaucescens, especially as found in Peninsular Malaysia and Borneo. The stouter habit of K losirensis possibly is partly due to more favourable conditions in forest on rich alluvial soil.