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The genus Cortinarius Fr. (Cortinariaceae, Agaricales) is divided into four or more subgenera. Dermocybe (Fr.) Sacc. has been recognized as either a subgenus of Cortinarius or a separate genus, distinguished in part by the presence of various anthraquinonic pigments. Nucleotide sequences of ribosomal DNA 5.8S and internal transcribed spacers were used to investigate the phylogenetic relationships among species of Dermocybe and selected taxa from subgenera of Cortinarius. Sequence data from 47 herbarium specimens representing 31 taxa (28 species plus 3 varieties) of Dermocybe and Cortinarius were analyzed using parsimony, maximum likelihood, and neighbor joining. In general, molecular data support the morphological groupings of the taxa, although they more closely correspond to biochemical (anthraquinone and other) analyses. Phylogenetic trees showed that, while the sections Dermocybe and Malicoriae are monophyletic, and the concolorous or almost concolorous red species (section Sanguineae, such as D. sanguinea and relatives) together formed a coherent clade, the subgenus Dermocybe sensu lato itself is polyphyletic. Cortinarius californicus clusters with taxa in Cortinarius, subgenus Telamonia, section Armillati. Dermocybe olivaceopicta is more closely related to other subgenera of Cortinarius than to Dermocybe. Within the genus Cortinarius, certain of the subgenera may actually represent coherent genera. Of the subgenera examined, Telamonia, Phlegmacium, and possibly Sericeocybe appear to represent well defined taxonomic groupings. However, current assignments of taxa within Leprocybe and Myxacium were inconsistent with the molecular data. Reorganization of some taxa and taxonomic groups is suggested. Key words: Dermocybe, Cortinarius, molecular phylogeny, rDNA, ITS1, ITS2.

We describe a method for extracting high molecular weight DNA from milligram amounts of fungus specimens. DNA extracted from 1 – 100 mg of fresh, air-dried, or lyophilized tissue was sufficient for 1–50 Southern hybridizations. Typical yields were 1 – 10 nanograms (ng) of DNA per milligram of starting material for fresh and air-dried samples, and 50–500 ng/mg for lyophilized samples. Of the 78 samples from 63 species of saprobic and ectomycorrhizal Basidiomycetes, all but one yielded measurable amounts of nucleic acids. The DNA was used for restriction enzyme ribosomal DNA hybridizations. While most species showed similarities in the genic regions, significant size variation was seen in the intergenic regions, in most cases allowing for distinction between samples at the species level.

Fungal biodiversity studies on the Olympic peninsula, Washington, have uncovered the key to understanding one of the most enigmatic mushroom genera worldwide. Discovery of a mushroom (Squamanita contortipes) on another grossly distorted but identifiable agaric (Galerina sp.), which retained partial fertility and morphology, provides documentation of parasitism and gall formation by the genus Squamanita. This revelation leads to a reinterpretation of all Squamanitas as commingled hosts and parasites and supplies a simple explanation for anatomical mixtures of tissues erroneously cited as evidence linking the Agaricaceae, Tricholomataceae, and Amanitaceae. It also resolves six decades of controversy over the identity or function of enlarged bases that often bear chlamydospores. Parasitism of mushroom fruit bodies by other mushrooms is a rare phenomenon (< 20 reported species globally). With the addition of accepted Squamanita species, the number of known sporophorous parasitic agarics worldwide is increased by one-third and the number of obligate mycoparasitic mushroom genera is doubled. Key words: biodiversity, gall, taxonomy, biology, terminology, chlamydospores, Pacific Northwest, Asterophora.