Phaeocollybia in western North America. I. ThePhaeocollybia kauffmanii complex
Morphological and molecular investigations during a taxonomic reevaluation of the genus Phaeocollybia revealed four new agaric species from British Columbia, Washington, Oregon, and California that are morphologically similar to Phaeocollybia kauffmanii (Smith) Singer. All five species produce large basidiomes with brown pilei, stipes with cartilaginous rinds surrounding dense pith, vertical-monopodial pseudorhizae, large, verrucose or verruculose, apically beaked basidiospores, and thin-walled, clavate cheilocystidia. The most salient morphological characters distinguishing the new species from P. kauffmanii include abundant clamp connections (Phaeocollybia ammiratii), a pink- or purple-brown pileus lacking encrusting pigments in the pileipellis (Phaeocollybia benzokauffmanii), a nonviscid, fibrillose, ochraceous pileus with a trilaminate pileipellis (Phaeocollybia luteosquamulosa), and unusually large basidiospores and subglobose subcapitate pedicellate cheilocystidia (Phaeocollybia redheadii). An emended description of P. kauffmanii accompanies technical descriptions and a key to the five species and newly revealed complex.Key words: Agaricales, Basidiomycota, Cortinariaceae, RFLPs, temperate rainforest.