Tree (5-)10-35 m. Leaves (membranous or) thinly chartaceous, elliptic-oblong or oblong-lanceolate, 9-22(-28) by 3.5-7(-10.5) cm, base short attenuate or rounded, apex acute(-acuminate); Inflorescences among the leaves or below, of the Knema-type: Fruits solitary, or 2 or 3 together, ellipsoid-oblong, 3-4.5(-6) by 2.5(-3) cm, apex rounded, base rounded or somewhat narrowed, hairs dense, bright (dark) rusty, 0.5-1 mm, rough especially towards the base of the fruit;
Asia-Tropical, Madang present, Morobe present, NE Papua Barat present, Papua New Guinea present, Sepik present, northern and eastern New Guinea present
Malesia: northern and eastern New Guinea (NE Papua Barat; Papua New Guinea: Sepik, Morobe, Madang Provinces).
Foreman (1978), following Sinclair (1968), described the male flowers with perianths 8-10 by 4-5 mm, possibly based on Brass 28894, a collection here placed in M. simulans. The perianth of this collection (in L) measures 8 by 4.5 mm; the androphore is glabrous. Sinclair noted that Brass 28894 had a deviating indumentum. The caption under Sinclair's figure 44 seems to be either erroneous, or the specimen drawn does not belong to M. buchneriana.