Cortinarius, subgenus Phlegmacium, section Phlegmacium in Europe. A study of character variation and ecology including a numerical analysis of the C. argutus complex

Abstract

The taxonomy of Cortinarius section Phlegmacium in Europe is treated, including 18 taxa, with emphasis on an analysis of character variation and differentiation as a tool for species delimitation and the selection of diagnostic characters. Based on the character differentiation between closely related taxa, spore size, veil structure, veil pigment and pileipellis structure appeared to be the most taxonomic significant characters in the group, whereas characters related to carpophore size and shape were of little value. A numerical (multivariate) analysis was performed including four taxa in subsect. Arguti. The PCO and cluster analysis distinguished more or less completely the four taxa, and a character analysis revealed discontinuous variation in at least one character between the taxa. The spore morphology characters were the most distinguishing. The taxonomic implications of the character variation are discussed. The species of sect. Phlegmacium have very specialized habitat requirements, with strict mycorrhizal associations. Of the 17 species here accepted, 16 appear to be associated with a single host genus in Europe, and most are associated solely with a single host species. Many species are calciphilous, xerophilous and thermophilous, and some have a strictly southern distribution in Europe. The majority of taxa are widely distributed, frequently following the natural distribution of their host trees.