Cortinarius lucorum (Fr.) Karst., a Populus associate from North America

Cortinarius lucorum is reported from low-elevation forests in Washington where it associates with Populus trichocarpa. It shares affinities with C. saturninus, a species associated with Salix, Populus, Corylus, and perhaps other woody angiosperm hosts. Both species share a bulbous stipe, thick veil, and violaceous coloration in at least some part of the basidiomata. Analysis of nucleotide sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal RNA tandem repeat indicates a single base pair difference between North American and northern European material. These data also affirm the autonomy of C. lucorum and a possible sister relationship with C. saturninus.