The genus Mycoacia Donk (1931) originally contained four species, viz. M. fuscoatra (Fr. ex Fr.) Donk (type), M. uda (Fr.) Donk, M. stenodon (Pers.) Donk, and M. setosa (Pers.) Donk. This last species, however, is the type species of Sarcodontia S. Schulzer 1866. Later (1952) Donk considered M. setosa as generically distinct. The monotypic genus Sarcodontia has globose to subglobose spores with thickened walls and is parasitic, while Mycoacia has ellipsoid to allantoid thin-walled spores and is saprophytic. When Mycoacia and Sarcodontia are considered as congeneric (e.g. Nikolajeva, 1961), Sarcodontia is the correct name for the genus. Mycoacia and Sarcodontia are both classified in the Corticiaceae (Donk, 1964; Parmasto, 1968); they are characterized by the resupinate hydnoid ceraceous basidiocarp, the monomitic hyphal system and the smooth non-amyloid spores. The genera are closely related to Phlebia.