Basidiospore homoplasy and variation in the Inocybe chelanensis group in North America

We present a morphological and phylogenetic study of Inocybe chelanensis and other North American species of Inocybe that have unusually elongated nodulose spores. Taxonomy and illustrations of these species are provided, along with a key to these and similar species found in Europe and North America. The species concept of I. chelanensis is broadened to include the range of variation occurring for the species in North America. Despite similar basidiospore morphologies, I. chelanensis and I. candidipes are not closely related. Inocybe chelanensis is related more closely to I. stellatospora and I. candidipes is related to I. glabrodisca based on RPB1 and nLSU-rDNA nucleotide sequences. Distal enlongation of Inocybe basidiospores was achieved independently in at least two separate lineages of Inocybe. Inocybe candidipes and I. sierraensis are described as new.