Six newly described Inocybaceae from North America.

Six new species of Inocybaceae from North America are described as new. Most are common and widespread throughout eastern North America. Phylogenetic analyses of nuc rDNA ITS1-5.8S-ITS2 (ITS), harnessing numerous community science records, together with nuc 28S rDNA support the phylogenetic distinctiveness of each species with strong support values. Sequences of additional genetic loci, including RNA polymerase II largest subunit (rpb1) and second largest subunit (rpb2), were also produced to supplement the descriptions and strengthen future phylogenetic studies. Of these new taxa, three are described in Inocybe: I. albofusca, a smooth-spored species in the Flocculosa clade; I. communis, a nodulose-spored species in the Xanthomelas clade; and I. lincoffii, a nodulose-spored species in I. subsect. Napipedinae. Inosperma aureiavis is a member of the Maculatum clade, whereas Pseudosperma aurivetum is a member of the Umbrinellum clade. Mallocybe diabolica is a narrow-range endemic known only from southeastern Arizona and Mexico and is allied with the Heimii clade. Complete descriptions and illustrations are presented for each species.