Taxonomy and phylogeny of the Auriculariales (Agaricomycetes, Basidiomycota) with stereoid basidiocarps

In the present study, we investigate taxonomy of the Auriculariales with effused or cupulate, persistent basidiocarps; generic and species concepts are revised based on morphological and DNA evidences. The genus Eichleriella is reinstated to embrace ten closely related species with ellipsoid-ovoid basidia, and the genus type, Eichleriella incarnata, is placed to the synonyms of Eichleriella leucophaea. Eichleriella bactriana, Eichleriella desertorum and Eichleriella sicca are described as new to science. In addition, four species earlier treated as members of Exidiopsis or Heterochaete are combined to the genus. The genus name Heteroradulum (type Radulum kmetii) is introduced for seven species with large, obconical, stipitate basidia. Of them, Heteroradulum adnatum and Heteroradulum semis are described as new. Two new genera, Amphistereum (with two species, type Eichleriella schrenkii) and Sclerotrema (monotypic, type Exidiopsis griseobrunnea), are proposed; Hirneolina (monotypic, type H. hirneoloides) and Tremellochaete (with two species, type Exidia japonica) are restored as good genera. The type species of Heterochaete, H. andina, is congeneric with Exidiopsis (type E. effusa).