Tree 6 m. Leaves thinly coriaceous, ovate-oblong or elliptic(-oblong), 19-25 by 9-12 cm, base (broadly) rounded, apex bluntly acute or short acute-acuminate; Inflorescences among the leaves, sessile, of the Knema-type;
Asia-Tropical, Idenburg River, 15 km SW of Bernhard Camp present, Papua Barat present
Malesia: Papua Barat (Idenburg River, 15 km SW of Bernhard Camp); known only from the type.
Myristica brassii was treated under M. sphaerosperma by Foreman . The two may be related, but M. brassii is quite distinguishable in details. A good differentiating character is the absence of dots on the lower leaf surface in M. sphaerosperma, a character which holds true on the species level for all Myristicas. Myristica brassii also seems closely related to M. cucullata (see there).