Cortinarius parkeri, a new species from the Pacific Northwest of North America

Abstract

Cortinarius parkeri , a new vernal species in subgenus Cortinarius , section Veneti , is described from the Pacific Northwest of North America. Within its subgenus, C. parkeri is unique in that its membranous universal veil is attached to the pileus edge of young mushrooms and extends as a covering over the pileus surface. At maturity, the universal veil forms a sheathing membranous volva-like structure that flares out above the stipe base. Sequences of the nuclear ribosomal DNA internal transcribed spacer region (ITS1-5.8s-ITS2) determined for 13 collections of C. parkeri were all identical, except for a polymorphic two base pair indel. In a phylogeny including other related species from North America and Europe, C. parkeri is monophyletic. In contrast to intraspecific distances, the interspecific genetic distance between C. parkeri and other Veneti species sequences was large. Being dikaryotic, mushrooms of C. parkeri contain genomes from two parents. As expected in a dikaryon in an interbreeding population, the polymorphic indel was homozygous in some collections but heterozygous in three collections, with conflicting sequences resulting from mixed parental types. Taken together, morphological and molecular results strongly support C. parkeri as a new and distinctive species.