biostudies-literatureUnknown90Na QBluish <i>Mycena</i> are rare, but constitute a taxonomically complex group. A total of eight bluish species in four sections have previously been reported from North America, Europe, Oceania and Asia. Two species with a blue pileus, collected in China during our taxonomic study of <i>Mycena</i> s.l., are described here as new to science: <i>Mycenacaeruleogrisea</i> <b>sp. nov.</b> and <i>M.caeruleomarginata</i> <b>sp. nov.</b> Detailed descriptions, line drawings and a morphological comparison with closely-related species, especially herbarium specimens of <i>M.subcaerulea</i> from the USA, are provided. The results of Bayesian Inference and Maximum Likelihood phylogenetic analyses of a dataset of 96 nuclear rDNA ITS and 20 nLSU sequences of 43 <i>Mycena</i> species are also presented. The morphological data and the results of the phylogenetic analyses support the introduction of <i>M.caeruleogrisea</i> and <i>M.caeruleomarginata</i> as new species. A taxonomic key to bluish <i>Mycena</i> species of sections <i>Amictae</i>, <i>Cyanocephalae</i>, <i>Sacchariferae</i> and <i>Viscipelles</i> is provided.MycoKeys119-145https://www.ebi.ac.uk/biostudies/studies/S-EPMC9849084biostudies-literatureTaxonomic studies of bluish <i>Mycena</i> (Mycenaceae, Agaricales) with two new species from northern China.PMC9849084Na QLiu ZGe YZeng HCheng XSong ZKe BfalseTaxonomic studies of bluish <i>Mycena</i> (Mycenaceae, Agaricales) with two new species from northern China.Bluish <i>Mycena</i> are rare, but constitute a taxonomically complex group. A total of eight bluish species in four sections have previously been reported from North America, Europe, Oceania and Asia. Two species with a blue pileus, collected in China during our taxonomic study of <i>Mycena</i> s.l., are described here as new to science: <i>Mycenacaeruleogrisea</i> <b>sp. nov.</b> and <i>M.caeruleomarginata</i> <b>sp. nov.</b> Detailed descriptions, line drawings and a morphological comparison with closely-related species, especially herbarium specimens of <i>M.subcaerulea</i> from the USA, are provided. The results of Bayesian Inference and Maximum Likelihood phylogenetic analyses of a dataset of 96 nuclear rDNA ITS and 20 nLSU sequences of 43 <i>Mycena</i> species are also presented. The morphological data and the results of the phylogenetic analyses support the introduction of <i>M.caeruleogrisea</i> and <i>M.caeruleomarginata</i> as new species. A taxonomic key to bluish <i>Mycena</i> species of sections <i>Amictae</i>, <i>Cyanocephalae</i>, <i>Sacchariferae</i> and <i>Viscipelles</i> is provided.2022-01-01T00:00:00Z20222026-04-08T12:48:10.056Z2025-04-04T21:15:26.245ZS-EPMC98490843676041810.3897/mycokeys.90.78880