The type specimens of Perenniporia contraria and of its presumed taxonomic synonym, Fomes subannosus, have been revisited. In addition, some recent collections identified as P. contraria have been re-examined, demonstrating that the present concept of the latter has been confused. The species concept is redefined and illustrated. Fomes subannosus, though closely related to P. contraria, is recognized as a distinct taxon on the basis of basidiocarp shape, pore size and the width of skeletal hyphae. The taxonomic placement of both taxa is discussed. Both species are endemic to neotropical America. All other specimens examined and originating from other continents belong to different taxa.