Speciation and phylogenetic distances within Paxillus s. str. (Basidiomycetes, Boletales)

This study aimed to elucidate the phylogenetic relationships within Paxillu s s. str. Collections of the Paxillus involutus complex from different habi tats have been compared. DNA sequence data were generated from the nuclear encoded 28S gene and the ITS region. Phylogenetic analyses of the two data sets showed three clearly differentiated groups within Paxillus s. str. Col lections from gardens and park areas under Betula, Corylus, Populus, Quercu s and Tilia showed to have a very close relationship to the North American species Paxillus vernalis, but are separated from P. involutus collections found in forests as well as from P. filamentosus. Possible taxonomic conclu sions are discussed.