Three new species of Gymnopus and Mycena (Agaricales, Basidiomycota) from Northwestern China

Members of the genera <i>Gymnopus</i> and <i>Mycena</i> are vital for litter decomposition in tropical and humid temperate forests. In this study, the difference in morphological features among <i>Gymnopus gansuensis</i>, <i>Gymnopus subsepiiconicus</i>, and <i>Mycena glabera</i> was confirmed by DNA data. <i>Gymnopus gansuensis</i> and <i>Gymnopus subsepiiconicus</i> showed separate relationships with other species in the ITS and nLSU combined dataset utilized for the phylogeny of <i>Gymnopus</i> sect. <i>Impudicae</i>. In addition, <i>Gymnopus gansuensis</i> is characterized by pileus honey yellow at the center, margin pinkish buff to buff, stipe pinkish buff to fuscous, and basidiospores elliptic to briolette. <i>Gymnopus subsepiiconicus</i> is characterized by pileus clay buff to grayish brown at the center, margin pinkish buff to fawn, stipe dark brown to fuscous, and basidiospores elliptic. Based on the combined dataset of the ITS and TEF-1α, <i>Mycena glabera</i> has been detected as a separate lineage in the phylogenetic studies of <i>Mycena</i> sect. <i>Calodontes</i>. The ecological behaviors of the new species are described with illustrations.