Taxonomy plays a central role in understanding the diversity of life, translating the products of biological exploration and discovery specimens and observations into systems of names that settle a “classification home” to taxa. Up to this point, studies on the taxonomy and phylogeny of the basidiomycetous genus Tomentella stemmed mainly from the temperate to boreal zones of the North Hemisphere, but were scarce in tropical Asia. In this study, four new species, viz. Tomentella olivaceobasidiosa, T. velutina, T. wumenshanensis and T. yunnanensis from China, are described and illustrated based on the morphological characteristics and molecular phylogenetic analyses, in which the sequences of ITS+nLSU+mtSSU+RPB2 genes were used for the phylogenetic analyses using Maximum Likelihood, Maximum Parsimony and Bayesian Inference methods. All the new species can be well recognised by their macroscopical and anatomical characteristics. The four new species, closely related taxa in the phylogenetic tree and morphologically similar species are discussed.

Taxonomy plays a central role in understanding the diversity of life, translating the products of biological exploration and discovery specimens and observations into systems of names that settle a “classification home” to taxa. The ectomycorrhizal basidiomycetes family Thelephoraceae has been understudied in subtropical ecosystems. Many species of Thelephoraceae are important edible and medicinal fungi, with substantial economic value. Four new species, Thelephora resupinata, T. subtropica, T. yunnanensis, and Tomentella tenuifarinacea, are proposed based on a combination of the morphological features and molecular evidence. Thelephora resupinata is characterized by the resupinate basidiomata having a tuberculate pileal surface hymenial, and the presence of the subglobose to globose basidiospores (9–12 × 7–9 µm). T. subtropica is solitary coriaceous infundibuliform gray-brown basidiomata with a presence of the subclavate basidia and subglobose to globose basidiospores (6–8 × 5–7 µm). T. yunnanensis is typical of the laterally stipitate basidiomata having a smooth, umber to coffee hymenial surface, a monomitic hyphal system with clamped generative hyphae, and the presence of the subglobose basidiospores (7–10 × 6–8 µm). Tomentella tenuifarinacea is typical of the arachnoid basidiomata having a smooth, gray, or dark gray hymenial surface, a monomitic hyphal system with clamped generative hyphae, and the presence of the subglobose to globose basidiospores (7–9 × 6–8 µm). Sequences of ITS+nLSU+mtSSU genes were used for the phylogentic analyses using maximum likelihood, maximum parsimony, and Bayesian inference methods. The three genes’ (ITS+nLSU+mtSSU) phylogenetic analysis showed that the genera Thelephora and Tomentella grouped together within the family Thelephoraceae and three new species were nested into the genus Thelephora, and one new species was nested into the genus Tomentella.