Diversity of the Genus Xylaria in European Atlantic Lauroid Forest: New Records and Description of Eight New Species

The genus Xylaria (Xylariaceae, Ascomycota) comprises a morphologically and ecologically diverse group of fungi with a predominantly saprobic lifestyle, widely distributed in forest ecosystems worldwide. Despite its global occurrence, its diversity in European Atlantic laurel forests (laurisilva), both insular and continental, remains poorly understood. In this study, we examined more than 80 collections of Xylaria from laurisilva forests in Madeira and the Azores (Portugal), the Canary Islands (Spain), and relict laurel woodlands in mainland Iberia, documenting at least 13 species. Several collections could not be successfully sequenced, suggesting that additional taxa may occur. Among the identified species, eight are described here as new to science and are supported by morphological differences and multilocus phylogenetic analyses. Species delimitation was based on an integrative approach combining detailed morphological observations with phylogenetic inference from ITS, LSU, RPB2, and TUB2 loci. Our results reveal a substantially higher diversity of Xylaria in these ecosystems than previously recognized and confirm the importance of multilocus frameworks for resolving species boundaries, particularly in morphologically cryptic lineages. This study expands the known diversity of Xylaria in Europe and identifies Atlantic laurel forests as important reservoirs of fungal diversity and evolutionary novelty.