Many polypores look very similar in nature and the same species in different parts of the world may appear to be different because of environmental conditions.
The information below can be used to distinguish closely related species from Polyporus alveolaris. All of these also have diamond shaped pores.
Polyporus squamosus: The basidiocarps are usually 0.5-2 centimeters (cm) thick with angular pores. The upper surface is a buff pale and the pore surface is buff to light brown. Stipe has a thin black cuticle at the base. The spores are cylindrical, hyaline, smooth, and 16-20 × 6-9 um.
Polyporus tuberaster: The basidiocarps are usually 0.5-2 cm thick with angular pores. The upper surface is whitish with small tan to dark brown scales. The spores are cylindrical to oblong ellipsoid, hyaline, and their size is 10-16 × 4-7 um.
Polyporus tenuiculus: The pileus can be smooth and scurfy, but usually evenly colored; sometimes there may be radial lines present. The upper surface is grayish, white, or ochraceous to tan. This species is found in small clusters from one point of attachment. The spores are cylindrical to subnavicular with tapering ends and the size is 9-12 × 2-3.5 um.