Morphological characteristics and phylogenetic analyses reveal five new species of Hymenochaetales (Agaricomycetes, Basidiomycota) from southwestern China.

Wood-inhabiting fungi can decompose wood materials and play a crucial role in the natural world by maintaining the equilibrium of the Earth's ecosystems. In the present study, five new wood-inhabiting fungal species belonging to the order Hymenochaetales, , , , and , collected from southern China, are proposed based on a combination of morphological features and molecular evidence. is characterized by a coriaceous, tuberculate hymenial surface, a monomitic hyphal system with simple-septate generative hyphae, and ellipsoid to narrow ellipsoid basidiospores (4.0-5.0 × 2.0-3.0 µm); is characterized by pruinose hymenial surface, a monomitic hyphal system with clamped generative hyphae, and broadly ellipsoid basidiospores (6.0-7.0 × 5.0-6.0 µm); is characterized by the cracked hymenial surface, clamped generative hyphae, and elliposoid basidiospores (4.0-5.5 × 2.7-3.5 µm); is characterized by an arachnoid hymenial surface, a monomitic hyphal system with clamped generative hyphae and cylindrical to allantoid basidiospores (4.0-6.0 × 1.5-2.2 µm) and is characterized by an arachnoid hymenial surface, a monomitic hyphal system with clamped generative hyphae and broadly ellipsoid to globe basidiospores (4.0-5.5 × 3.5-5.0 µm). Sequences of the internal transcribed spacers (ITS) and the large subunit (nrLSU) of the nuclear ribosomal DNA (rDNA) markers of the studied samples were generated. Phylogenetic analyses were performed using maximum likelihood, maximum parsimony, and Bayesian inference methods. Full descriptions, illustrations, and phylogenetic analysis results for the five new species are provided.