A variety described from the Great Lakes region, var. "uliginosus", was recognised by Alexander H. Smith and Harry D. Thiers in 1971 on the basis of its microscopic features, a distinction supported by Professor C.B. Wolfe of Pennsylvania State University. However, "Index Fungorum" does not consider this an independent taxon. Similarly, "Boletus felleus" var. "minor", published originally by William Chambers Coker and A.H. Beers in 1943 (later transferred to "Tylopilus" by Albert Pilát and Aurel Dermek in 1974), has been folded into synonymy with "T. felleus". Charles Horton Peck described "Boletus felleus" var. "obesus" in 1889, but no record of a type specimen exists. Although some records exist of "T. felleus" in Australia, their spores are of consistently smaller dimensions and this taxon has been classified as a separate species, "T. brevisporus".