Tylopilus

The genus was first defined by Petter Adolf Karsten in 1881.^[6] The type species, Tylopilus felleus, was originally described in 1788 as a species of Boletus by French mycologist Pierre Bulliard.^[7] Tylopilus means "bumpy or swollen pileus",^[8] from the Greek tylos "bump" and pilos "hat".^[9]

Molecular analysis indicates the genus, like other large genera within the Boletales, is polyphyletic.^[10] A lineage of Tylopilus chromapes (now Harrya chromapes and related species) has been shown to be only distantly related to other members of Tylopilus. Hence T. chromapes is now the type species of the new genus Harrya and, related to it, several Australian species moved to Australopilus.^[11] T. valens was also moved to its own genus, Pseudoaustroboletus.^[12]

Fruit bodies of the genus Tylopilus are encountered as large stout bolete mushrooms, which generally arise from the ground or occasionally from wood. They have stout stipes, which do not have a ring.^[8] A key field character which distinguishes them from members of the genus Boletus is the presence of their pink-tinged pores (though these may be white when young).^[13] The "pink pore" feature is a polyphyletic morphology that does not unite the Tylopilus species using traditional morphological characters (Smith and Thiers or Singer's concepts). The spore print manifests various shades of pinkish-brown, through reddish-brown and even chocolate brown.^[8]

Many species have a bitter-metallic taste and are thus inedible,^[8] taste being a key feature in the identification of boletes.^[13] The black velvet bolete (T. alboater) is a good edible, but is often ignored.^[8]

As of January 2024^[update], Index Fungorum recognises 146 species in the genus Tylopilus.^[14] At least 40 are found in western North America.^[8] A large number have been recorded from Australia, with 26 aligned with existing taxa and another 15 not assignable. Members of the genus are also abundant in South America, particularly in forests with trees of the genus Dicymbe in Guyana, as well as Central America and elsewhere across tropical regions around the world.^[15] All are mycorrhizal.