Abstract
In a comprehensive survey of fungi conducted in the northern (Chiang Rai Province) and southern (Narathiwat Province) regions of Thailand, several xylariales-like specimens were discovered. Through the integration of molecular phylogeny and morphological analyses, one previously undocumented taxon, Oxydothis narathiwatensissp. nov., was identified, along with Xylaria bawanglingensis and Hypoxylon hypomiltum as new host and geographical records from Afzelia xylocarpa, and Dalbergia cana, respectively. In addition, Annulohypoxylon thailandicum was identified as a new host record from Swietenia macrophylla in Thailand. The morphological characters, including ascomata, asci, and ascospores, were compared with known Oxydothis, Xylaria, Hypoxylon, and Annulohypoxylon species. Multi-locus phylogenetic analyses based on ITS, LSU, and SSU (for Oxydothidaceae), ITS, rpb2, tub2, and act (for Xylariaceae), and ITS, LSU, rpb2, and tub2 (for Hypoxylaceae) gene regions were carried out to refine the taxonomic classifications of these specimens further. This research contributes to understanding fungal diversity in these ecologically significant regions, highlighting insights into the relationships among xylariales-like species.