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.

Six field surveys were carried out in Zixishan area, Yunnan Province, China during 2016–2021, and 1407 specimens of wood-decaying fungi were collected. The paper summarizes the obtained results on the wood-decaying fungi of this area, consisting of 74 species belonging to 49 genera, 24 families and 7 orders. Polyporales is the dominant order (51.35% of the total species), and Hyphoderma, and Peniophorella are the dominant genera (Each accounted for 6.76% of the total) in this area. Their hosts and substrates were also identified and a checklist of wood-decaying fungi is provided. The taxa were identified by morphology and molecular evidence. The sequences of the Internal Transcribed Spacer (ITS) gene region of the studied specimens were generated and the phylogenetic analyses were performed. Five new species were earlier described in Zixishan area viz. Hyphoderma fissuratum C.L. Zhao & X. Ma (2021: 37), H. microporoides C.L. Zhao & Q.X. Guan (2021: 9), H. tenuissimum C.L. Zhao & Q.X. Guan (2021: 153), Hyphodermella zixishanensis C.L. Zhao (2021: 4), and Phanerochaete pruinosa C.L. Zhao & D.Q. Wang (2021: 8). This work aimed to provide an updated checklist of wood-decaying fungi in Zixishan area, Yunnan Province, China, as well as to enrich the knowledge of the fungal diversity in China and worldwide.

The wood-inhabiting fungi play a crucial role in wood degradation and the cycle of matter within the ecological system. They are considered the “key player” in wood decomposition because of their ability to decompose woody lignin, cellulose, and hemicellulose. Steccherinum farinaceum is described and illustrated based on morphological and molecular evidence. This species is characterized by white to cream basidiomata with farinaceous hymenophore and ellipsoid to subglobose basidiospores (4.0–5.5 × 3.5–4.5 µm). Sequences of the internal transcribed spacer region (ITS) and the large subunit nuclear ribosomal RNA gene (nLSU) from the studied samples were generated, and phylogenetic analyses were performed using Maximum Likelihood, Bayesian Inference, and Maximum Parsimony methods. The phylogenetic analysis indicated that the new species S. farinaceum is nested within the genus Steccherinum and is sister to two related species, S. wumengshanense and S. yunnanense. A description, illustrations, and phylogenetic analysis results of the new species are provided. Additionally, the new species is compared with closely related taxa.