A preliminary ITS phylogeny of Melanoleuca (Agaricales), with special reference to European taxa

Ninety-one Melanoleuca collections were chosen to test the agreement of current and traditional infrageneric tripartite classifications of Melanoleuca (subgenera Acystis without cystidia, Urticocystis with urticiform cystidia, and Melanoleuca with macrocystidia) with molecular phylogenetic data (ITS sequences analysis) and to evaluate the systematic significance of relevant morphological characters. Melanoleuca is found to be monophyletic, and only two emended subgenera, Urticocystis and Melanoleuca, are supported. Subg. Urticocystis comprises all taxa with urticoid cystidia plus the macrocystidiate M. cognata complex. The artificial subg. Acystis is shown to be polyphyletic and no longer tenable. The entire genus comprises at least 10 clades with 13 subclades. Melanoleuca sublanipes sp. nov. and new combinations M. exscissa f. iris, M. exscissa f. sarcophylla, M. exscissa f. diverticulata, and M. paedida f. electropoda are introduced.