Russula atroaeruginea and R. sichuanensis spp. nov. from southwest China

Two new species of Russula are described from southwestern China based on morphology and ITS1-5.8S-ITS2 rDNA sequence analysis. Russula atroaeruginea (sect. Griseinae) is characterized by a glabrous dark-green and radially yellowish tinged pileus, slightly yellowish context, spores ornamented by low warts linked by fine lines, and numerous pileocystidia with crystalline contents blackening in sulfovanillin. Russula sichuanensis, a semi-sequestrate taxon closely related to sect. Laricinae, forms russuloid to secotioid basidiocarps with yellowish to orange sublamellate gleba and large basidiospores with warts linked as ridges. The rDNA ITS-based phylogenetic trees fully support these new species.