Infragenic phylogeny of Collybia s. str. based on sequences of ribosomal ITS and LSU regions

Collybia, as understood by Antonin & Noordeloos. comprises four species: C. racemosa C. tuberosa, C. cirrhata and C. cookei. Collybia tuberosa. C. cir rhata and C. cookei are morphologically similar and are primarily distingui shed from each other by the presence or absence and the colour of sclerotia . All four share a common and unique habitat. Phylogenetic reconstructions using DNA sequences of the ribosomal ITS1-5.8S-ITS2 support four distinct c lades, each corresponding to a morphological species, with the C. tuberosa. C. cirrhata and C. cookei clades forming a larger group. Analyses of ribos omal Large Subunit DNA sequences confirmed that Collybia tuberosa, C. cirrh ata and C. cookei formed a monophyletic group. In both analyses, the C. rac emosa sequence was highly divergent from those of the other three species o f the complex and we propose a separate genus name, Dendrocollybia, for thi s species. Simple diagnostic RFLP patterns were identified for the four spe cies and were used to validate morphological designations and distributions .