Resolution of morphology-based taxonomic delusions: Acrocordiella, Basiseptospora, Blogiascospora, Clypeosphaeria, Hymenopleella, Lepteutypa, Pseudapiospora, Requienella, Seiridium and Strickeria

Fresh material, type studies and molecular phylogeny were used to clarify phylogenetic relationships of the nine genera Acrocordiella, Blogiascospora, Clypeosphaeria, Hymenopleella, Lepteutypa, Pseudapiospora, Requienella, Seiridium and Strickeria. At first sight, some of these genera do not seem to have much in common, but all were found to belong to the Xylariales, based on their generic types. Thus, the most peculiar finding is the phylogenetic affinity of the genera Acrocordiella, Requienella and Strickeria, which had been classified in the Dothideomycetes or Eurotiomycetes, to the Xylariales. Acrocordiella and Requienella are closely related but distinct genera of the Requienellaceae. Although their ascospores are similar to those of Lepteutypa, phylogenetic analyses do not reveal a particularly close relationship. The generic type of Lepteutypa, L. fuckelii, belongs to the Amphisphaeriaceae. Lepteutypa sambuci is newly described. Hymenopleella is recognised as phylogenetically distinct from Lepteutypa, and Hymenopleella hippophaëicola is proposed as new name for its generic type, Sphaeria (= Lepteutypa) hippophaës. Clypeosphaeria uniseptata is combined in Lepteutypa. No asexual morphs have been detected in species of Lepteutypa. Pseudomassaria fallax, unrelated to the generic type, P. chondrospora, is transferred to the new genus Basiseptospora, the genus Pseudapiospora is revived for P. corni, and Pseudomassaria carolinensis is combined in Beltraniella (Beltraniaceae). The family Clypeosphaeriaceae is discontinued, because the generic type of Clypeosphaeria, C. mamillana, is a member of the Xylariaceae. The genus Seiridium, of which the sexual morph Blogiascospora is confirmed, is unrelated to Lepteutypa, as is Lepteutypa cupressi. The taxonomy of the cypress canker agents is discussed. The family Sporocadaceae is revived for a large clade of the Xylariales that contains Hymenopleella, Seiridium and Strickeria among a number of other genera. Neotypes are proposed for Massaria fuckelii and Sphaeria hippophaës. Didymella vexata, Seiridium marginatum, Sphaeria corni, Sphaeria hippophaës, Sphaeria seminuda are epitypified, Apiosporina fallax, Massaria occulta, Sphaeria mamillana and Strickeria kochii are lecto- and epitypified. We also provide DNA data for Broomella vitalbae, Cainia desmazieri and Creosphaeria sassafras.