A new species of Pluteus sect. Hispidoderma (Agaricales, Basidiomycota) from the Far East, Russia

Pluteus svetlanae collected from birch wood in broadleaved mountain forest in Sikhote-Alin State Nature Biosphere Reserve, the Russian Far East, is described as a new species, based on its distinctive morphology and phylogeny. The fungus is characterized by small basidiomata having pale brown or beige pileus with striate and granulose-pruinose surface, whitish floccose stipe with subbulbose base, pileipellis as trichohymeniderm, and broadly fusiform or lageniform pleurocystidia with subcapitate apex and lateral projections. A phylogenetic analysis based on molecular data (ITS1-5.8S-ITS2 region) was conducted to explore the relationship of the new species. Results place the new species in sect. Hispidoderma. Detailed morphological description, field photograph, original drawing of microstructures, and comparison of the new species with other morphologically and phylogenetically closely related species are provided.