Phylogenetic relationships of some members in the genus Hymenoscyphus (Ascomycetes, Helotiales)

The relationships among some species of Hymenoscyphus and a few genera in other families of the Helotiales with somewhat similar excipular structure were investigated based on sequence analyses of the rDNA ITS1-5.8S-ITS2 region. The phylogenetic trees were established with Lachnum spartinae and L. cf. pygmaeum as outgroup. Two clades were recognized within Hymenoscyphus. Hymenoscyphus fructigenus, the lectotype of the genus, together with H. caudatus, H. cf. fructigenus, H. fucatus, H. cf. menthae, and H. scutulus, as well as H. epiphyllus, H. immutabilis, H. lasiopodius, H. serotinus, and H. globus, represent a monophyletic group. Hymenoscyphus ericae, H. sp. G1, H. rhodoleucus, and Calycina herbarum form the other clade. Hymenoscyphus caudatus is possibly a species complex. Hymenoscyphus globus is described as a new species. The Erieaceae-associated species and Calycina herbarum treated formerly as members of Hymenoscyphus should be excluded from the genus and the family Helotiaceae. The new genus Rhizoscyphus is established to accommodate H. ericae and a related species.