Basionym Name:Agaricus difformis var. stygius Fr., Syst. mycol. (Lundae) 1: 170 (1821)
Homotypic synonyms:Camarophyllus difformis * stygius (Fr.) P. Karst., Bidr. Känn. Finl. Nat. Folk 32: 229 (1879)Clitocybe stygia (Fr.) Sacc., Syll. fung. (Abellini) 5: 191 (1887)