Tree 6-25 m. Leaves coriaceous, oblong(-lanceolate), 14-31 by 4.5-10.5 cm, base attenuate, apex up to 1.5 cm acute-acuminate; Inflorescences: Fruits 1 or 2 per infructescence, (immature) ellipsoid, 2 by 1.2 cm, with dense dark rusty dendroid hairs 0.2-0.3(-0.5) mm;
Asia-Tropical, Central Sulawesi present, northern SE Peninsula, N side of Lake Matano present
Malesia: Central Sulawesi (northern SE Peninsula, N side of Lake Matano).
1 Knema matanensis seems related to species in the group of K. glauca (with, e.g., K cinerea, K glauca, and K. kinabaluensis); it seems particularly related to K kostermansiana, a species also with small globose male buds, and the bracteole apically on the pedicel, but differing in membranous leaves with cordate base, 8-10 anthers, and caducous bracteole. 2 Knema matanensis (and K. stellata subsp. minahassae) was not seen in the area with ultrabasic rock south of Lake Matano, where K. celebica exclusively was found.