Paxillus orientalis sp. nov. (Paxillaceae, Boletales) from south-western China based on morphological and molecular data and proposal of the new subgenus Alnopaxillus

The new species Paxillus orientalis is reported from Yunnan Province (south-western China). Based on morphological and molecular characters the novel taxon belongs to the sibling, holarctic alder-associated P. rubicundulus complex. Colour pictures of fresh basidiomes and line drawings are provided, accompanied by notes concerning its taxonomic and phylogenetic relationships within the genus. The new subgenus Alnopaxillus is established to accommodate P. rubicundulus and allied undescribed taxa characterized by basidiomes usually associated with Alnus and with a distinctly areolate–squamulose pileal surface.