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 .