Additions to the coriaceous families Peniophoraceae and Stereaceae (Russulales): Six novel wood-inhabiting taxa in the genera , , and from southwest China.

Russulales comprises a highly diverse group of species with respect to basidiomata morphology and hymenophore configuration, in which this order is highly heterogeneous, that can be classified as resupinate, effused-reflexed, discoid, clavarioid, pileate, or stipitate, and with varied hymenophores such as smooth, hydnoid, poroid, and lamellate in different russuloid species. Species in Russulales have been considered to have significant economic value. Six new wood-inhabiting fungi belonging to the genera , , and of two families, Peniophoraceae and Stereaceae (Russulales), were found in southwest China. Sequences of ITS+nLSU loci of six new taxa were generated, and phylogenetic analyses were performed with the maximum likelihood, maximum parsimony, and Bayesian inference methods with an emphasis on the phylogeny of wood-inhabiting smooth species in this order. The combined ITS+nLSU loci analysis showed that the six new species grouped within the order Russulales, in which , , and grouped into the family Stereaceae, and , , and grouped into the family Peniophoraceae. The morphology and multi-gene phylogenetic analyses confirmed the novelty and placement of the six new taxa. Descriptions, illustrations, and phylogenetic analysis results of the new taxa are provided.