Phylogenetic relationships of European Phlegmacium species (Cortinarius, Agaricales)

Phylogenetic relationships of 54 European Phlegmacium species, including members of most of the sections of classical systematics, were studied, integrating macro-, micromorphological and chemical characters of the basidiomes, as well as molecular phylogenetic analysis of nuclear rDNA sequences. Microscopical structures of the basidiomes were studied by light microscopy. Basidiospore morphology was examined by scanning electron microscopy. Internal-transcribed spacers (ITS 1 and 2, including the 5.8S) and the D1/D2 (LSU) regions of nuclear rDNA were sequenced and analyzed with a Bayesian Markov chain Monte Carlo approach. Many subgroups detected by the molecular analysis are related to groups known from classical systematical concepts. Among others, these subgroups were significantly supported: i) a group containing most of the members of section Fulvi ss. Brandrud and the species Cortinarius arcuatorum, C. dibaphus and C. multiformis; ii) a group comprising taxa of section Calochroi ss. Brandrud and the species C. fulvocitrinus and C. osmophorus; iii) a group containing species of section Glaucopodes ss. Brandrud and C. caerulescens; iv) a group including members of section Phlegmacioides ss. Brandrud; v) a group that includes the species C. cephalixus, C. nanceiensis and C. mussivus. Stipe shape, color of flesh, pigment contents, KOH reaction on pileipellis and gelatinous layer, degree of development of a gelatinous layer on the pileipellis, and pileipellis structure were useful characters in delimiting subgroups in Phlegmacium, while basidiospore morphology was significant at species level. With the exception of C. glaucopus, C. infractus and C. scaurus, ITS and D1/D2 sequences obtained from collections of the same species from different geographical origins showed very little variation. Our molecular and morphological analyses suggest revisions of the traditional concepts of the subgenus Phlegmacium in Europe.