Morphological and phylogenetic characterization of three new Cortinarius (Cortinariaceae, Agaricales) species in Yunnan, China

Through comprehensive morphological and phylogenetic investigations (ITS and nrLSU), we have delineated three novel species within Cortinarius, as derived from specimens collected in Yunnan Province, China. Cortinarius mucobrunneus is distinguished by its viscid basidiomata, dark brown pileus adorned with translucent stripes, cinnamon to brown lamellae, white stipe leaving a cinnamon ring on the upper part, and elliptical to amygdaliform, strongly verrucose basidiospores measuring 13.5–16 × 8–10 μm.

Cortinarius rugosiviscidus is characterized by sticky basidiomata, a light brown pileus with wrinkled surface, brown lamellae, light brown stipe, and elliptical to amygdaliform, moderately verrucose basidiospores measuring 11.5–15 × 7.5–9.5 μm. Cortinarius saloroides is characterized by its violet pileus with fine fibrous scales, mauve to light brown lamellae, bluish violet stipe leaving a light brown ring on the upper part, and subspherical, broadly elliptical to elliptical, moderately verrucose basidiospores measuring 7–8.5 × 5.5–6.5 μm.

Differences between the new species and morphologically similar and phylogenetically related species are discussed.