Identity of the subalpine–subarctic corticioid fungus Megalocystidium leucoxanthum (Russulales, Basidiomycota) and six related species

Background and aims – To date, Megalocystidium leucoxanthum, a corticioid fungus originally described from the Italian Alps, was considered as widely distributed species inhabiting numerous angiosperm hosts in northern hemisphere. Its specimens collected different geographic areas various host revealed high morphological variability thus obfuscated differences closely related M. luridum. The objective of this study to re-establish leucoxanthum based on newly sequenced clarify identity morphologically deviating collections previously ascribed species.Material methods In total, 87 spp. (including two historical types) were studied by methods. Their phylogenetic relations investigated DNA sequences (nrITS, nrLSU, tef1) 29 specimens.Key results Based morphological, ecological data, we showed sensu typi is rare restricted Alnus alnobetula subalpine subarctic zones. Consequently, records other (mostly representatives Salicaceae) belong three species, olens, perticatum, salicis, new science. fourth introduced pellitum, occurs same tree but it can be separated latter due distinctive traits sequences. Additionally, Aleurodiscus diffissus combined luridum clarified.