Morphological and ITS identification of Cortinarius species (section Calochroi) collected in Mediterranean Quercus woodlands

Abstract

Species of Cortinarius sect. Calochroi show a high grade of morphological variability in the Mediterranean region with regard to vicariant populations in the Eurosiberian region. This has contributed to confusion on taxonomy and nomenclature, especially when the variability affects the characters traditionally used for taxonomic delimitation. In this paper, we have attempted to clarify the taxonomy and nomenclature of several Calochroi taxa in the Mediterranean area by using macromorphological and spore analyses, as well as phylogenetic analysis of ITS sequences. We have demonstrated the usefulness of ITS sequences for species rank identification in Cortinarius (barcoding). We have been able to assign the studied material to eight species using ITS sequences (C. haasii, C. parasuaveolens, C. platypus, C. rickenianus, C. sancti-felicis, C. selandicus, C. splendidior and C. subgracilis), and to detect misidentified collections that were used by their authors to describe a new species (C. violaceipes). Moreover, molecular data have been useful to test the taxonomic value of morphological and spore characters. The morphological analysis has enabled us to detect morphological variability previously unreported in several taxa. A new variety, C. haasii var. quercus-ilicicola, is proposed on the basis of morphological and molecular data. Also, the taxonomic status of C. rickenianus is discussed. Finally, our results increase both the distribution area as well as the ecological preferences of five studied species, and several important biogeographical disjunctions are reported (C. selandicus and C. subgracilis).