Pine trees play a crucial role in the forests of Sichuan Province, boasting rich species diversity and a lengthy evolutionary history. However, research and investigation on fungi associated with pine trees are insufficient. This study investigated the diversity of hyphomycetes fungi associated with pine trees in Sichuan Province, China. During the survey, we collected five specimens of hyphomycetes from branches and bark of species of Pinus. Five barcodes were selected for study and sequenced, including ITS, SSU, LSU, TEF1, and RPB2. Morphological examination and multi-locus phylogenetic analyses revealed three new species, viz. Catenulostroma pini sp. nov. within Teratosphaeriaceae, Kirschsteiniothelia longisporum sp. nov. within Kirschsteiniotheliaceae, Sporidesmiella sichuanensis sp. nov. within Junewangiaceae, and two known species, Paradictyoarthrinium diffractum and P. hydei within Paradictyoarthriniaceae, which are the new host records from Pinus species. Catenulostroma pini, distinguished from other species in the genus by its unique morphology, has three conidial morphologies: small terminal helicoconidia, scolecoconidia with many septa, and phragmoconidia conidia. Kirschsteiniothelia longisporum has longer spores when compared to the other species in the genus. According to phylogenetic analysis, Sporidesmiella sichuanensis formed an independent clade sister to S. aquatica and S. juncicola, distinguished by differences in conidial size.

Pleosporales is a highly diverse (and the largest) order in Dothideomycetes, and it is widespread in decaying plants in various environments around the world. During a survey of fungal diversity in Sichuan Province, China, specimens of hyphomycetous and Thyridaria-like fungi were collected from dead branches of pine trees and cherry trees. These taxa were initially identified as members of Massarinaceae and Thyridariaceae through morphological examination. Phylogenetic analyses of the Thyridariaceae, combining ITS, SSU, LSU, RPB2, and TEF1 sequence data, indicated a distinct clade sister to Pseudothyridariella and Thyridariella, distinct from any genus in the family. Thus, a new genus, Vaginospora, is proposed to accommodate the type species Vaginospora sichuanensis, which is characterized by semi-immersed globose to oblong ascomata with an ostiolar neck, cylindrical to clavate asci with an ocular chamber, and hyaline to dark brown, fusiform, 3–5-transversely septate ascospores with an inconspicuous mucilaginous sheath. Based on the morphological comparisons and multi-locus phylogenetic analyses (ITS, SSU, LSU, RPB2, and TEF1) of the Massarinaceae, we have identified three collections belonging to the genus Helminthosporium, leading us to propose H. filamentosa sp. nov., H. pini sp. nov., and H. velutinum as a new host record. According to Phylogenetic analysis, H. pini formed an independent clade sister to H. austriacum and H. yunnanense, and H. filamentosa represents the closest sister clade to H. quercinum. Helminthosporium pini is distinct from H. austriacum by the shorter conidiophores and H. yunnanense by the longer and wider conidia. The H. filamentosa differs from H. quercinum in having longer conidiophores and smaller conidia. This study extends our understanding of diversity within Thyridariaceae and Helminthosporium. Our findings underscore the rich biodiversity and potential for discovering novel fungal taxa within these groups.

Tar spot is a prevalent fungal disease characterized by shiny black spots on the leaves, stems, and fruits of various plants. It is typically caused by members of the family Phyllachoraceae, which consists of biotrophic and obligate plant parasitic fungi. During field investigations of tar spot fungi in Sichuan Province, China, 70 fungal samples associated with tar spots belonging to the family Poaceae were collected from 13 different locations. Through morphological studies and multi-locus phylogenetic analysis of combined ITS, SSU, and LSU datasets, the collected samples were classified into eight Phyllachora species. Among these, five were identified as new species (Phyllachora cylindricae, P. festucae, P. luzhouensis, P. palmifoliae, and P. wenchuanensis), and two represented new host records (P. chongzhouensis, P. panicicola). The new species are accompanied by descriptions and illustrations, while their characteristics are discussed in relation to comparable taxa. Additionally, P. yuanjiangensis is synonymized under P. xinpingensis. These findings enhance our understanding of tar spot fungi in Sichuan and, given that Phyllachora species are important pathogens of plants in the Poaceae family, establish a foundation for further research to better understand their potential impacts on agriculture and the local ecology.