Morpho-molecular characterization reveals three Cortinarius subgenus Dermocybe species from southwest China (Agaricales, Cortinariaceae)

Cortinarius stands as the most extensive and morphologically distinctive genus within the Cortinariaceae. During our comprehensive surveys of macrofungi in southwestern China, we have collected mushroom specimens resembling Cortinarius and identified them as three new species: Cortinarius orienticroceus , C. orientisanguineus , and C. subolivaceoluteus , based on morphology and multi-locus phylogenetic analyses using maximum likelihood/Bayesian inference. Cortinarius orienticroceus is notable for its pileus, which is dark brown at the center and gradually lightens to a pale yellow at the edges; lamellae range from pale yellow to bright yellow, while the stalk is initially silky and shiny, later turning darker with a slight olive tint as it matures. Cortinarius orientisanguineus , on the other hand, features a dry, hemispherical pileus with noticeable fibrous scales, lamellae are reddish-brown, and the veil disappears over time, leaving a reddish-brown ring on the upper to middle part of the stalk. In contrast, Cortinarius subolivaceoluteus presents a pileus that starts papillate and flattens as it matures; the stalk is cinnamon-colored on the upper part, with tawny fibrils and patches below, and has a slightly bulbous base; the veil is cinnamon-colored and vanishes over time. Morphological illustrations and comprehensive morphological descriptions, along with phylogenetic relationships of other species within subg. Dermocybe of the three new Cortinarius species are provided. This research expands the taxonomic framework of subgenus Dermocybe through contemporary systematic approaches and emphasizes the substantial contribution of Chinese mycological collections to our understanding of this fungal group.