The Xeromphalina campanella/kauffmanii complex: species delineation and biogeographical patterns of speciation.

European, North American and northeastern Asian collections of Xeromphalina section Xeromphalina were studied by sequencing the nuc rDNA ITS1-5.8SITS2 and 28S 5' regions and partial RNA polymerase II second largest subunit gene (RPB2). Previously designated Xeromphalina campanella I is designated X.