Melanoleuca galbuserae, M. fontenlae and M. acystidiata—Three New Species in Subgenus Urticocystis (Pluteaceae, Basidiomycota) with Comments on M. castaneofusca and Related Species

Melanoleuca is one of the taxonomically most complicated genera of Agaricomycetes with several taxonomically lineages. The subgenus Urticocystis of the genus Melanoleuca contains species with either urticoid or absent cheilocystidia. In this paper, three new European species, Melanoleuca galbuserae, Melanoleuca fontenlae, and Melanoleuca acystidiata are described as new to science. Melanoleuca galbuserae, related to Melanoleuca stepposa and Melanoleuca tristis, was discovered in alpine grasslands in North Italy. The type specimens and recent collections of Melanoleuca angelesiana, Melanoleuca castaneofusca, Melanoleuca luteolosperma, Melanoleuca pseudopaedida, and Melanoleuca robertiana were sequenced and morphologically examined. Moreover, the related Melanoleuca microcephala and Melanoleuca paedida were included in morphological examination and DNA sequence analyses. All the species were delimited by macro- and micromorphological characters and the multigene phylogenetic analyses of a combined (ITS, rpb2, and tef1) dataset on the basis of the species tree estimation. In accordance with new molecular and morphological data, we suggest taxonomic reappraisal of M. pseudopaedida and M. robertiana, and M. fontenlae and M. acystidiata are proposed as new species. The differences between the type material of M. angelesiana from the USA and European M. angelesiana specimens are discussed.