Polyphasic taxonomy and chemical diversity of Annulohypoxylon (Ascomycota, Hypoxylaceae): New species from China’s tropical forest

As part of an ongoing inventory of Ascomycota in China, we examined species of the genus Annulohypoxylon collected from tropical forests. Through a comprehensive analysis encompassing phylogenetic, chemotaxonomic, and morphological data, we provide descriptions, illustrations, and diagnostic keys for 17 species. Among these, 14 are newly described species, while three represent new records for the studied region. In addition, evidence from phylogenetic, chemotaxonomic, and morphological analyses prompted the re-examination of the taxonomic status of Rostrohypoxylon , resulting in it being reduced to synonymy under Annulohypoxylon . This study underscores the large yet underexplored diversity of Hypoxylaceae in China’s tropical forests. While numerous Xylariales fungi have been documented in these regions, the diversity within the family Hypoxylaceae remains largely unexplored, leaving significant potential for further discoveries. Moreover, metabolomic profiling using ultrahigh performance liquid chromatography coupled to diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IMS-MS/ MS) revealed a hidden diversity of stromatal metabolites among the studied taxa, independent of their taxonomic relationships.