Mating systems in the Xerulaceae (Agaricales, Basidiomy cotina): Flammulina

Recently published taxonomic circumscriptions for taxa within Flammulina encouraged mating studies to confirm or reject these names or taxa. Three categories of pairing experiments were performed: 1) self-crosses of monokaryon isolates of exemplars of various putative taxa; 2) inter-exemplar pairings among exemplar strains; and 3) pairings between exemplars and 87 unidentified strains which were grouped on this basis. Mating experiments could distinguish F. velutipes from other taxa, but not among infraspecific taxa of F. velutipes (vars. velutipes, lactea , and lupinicolaJ and monokaryons of all these taxa were partially compatible with those of F. ononidis. Likewise, isolates of F. rossica and F. elastica were partially compatible with one another but incompatible with those of other taxa. All other taxa (F. mexicana, F. stratosa, F. populicola, F. fennae) appeared to be genetically isolated. Low levels of interspecific hybridization between F. velutipes and F. populicola , and between F. velutipes and F. rossicalelastica were also noted.