Evolution of the taxonomy of the genus Hypoxylon (Xylariales, Hypoxylaceae): Update on the current status of the names that have eventually been used for its species and virtual identification of Xylariales based on genome mining

The taxonomic status of all validly published names in the xylarialean genus Hypoxylon is herein assessed, relying on historical literature, as well as on more recently published work. Starting from traditional morphological concepts based on the teleomorphs via the inclusion of anamorphic traits and later on, molecular phylogenetic data, we have meanwhile arrived to the era of phylogenomic studies. Historic and currently available names in Hypoxylon were classified into six categories, each category reflecting what types of data and physical material, as well as their quality, are underlying and supporting each name, in a similar manner as in high school grading. Accordingly, taxa with available full genome sequences of the type material are ranked highest, while taxa where type material appears to be lost or depauperate are given the lowest classification. Among the latter are also the species that were erected, based on short reads environmental ITS sequences in times where it has become relatively easy and inexpensive to generate third generation full genome sequences. To demonstrate the power of genome mining for taxonomic purposes and the usefulness of our here proposed taxonomic framework of the genus Hypoxylon , several published full genomes from endophytic Hypoxylon spp. which were previously only identified at genus level were here finally classified to species level, whenever possible.