A Molecular and Morphological Reassessment ofDiademaceae

Abstract

We revisit the familyDiademaceaebased on available sequence data and morphology.Diademaceaeis characterized by ascomata opening with a flat circular lid and fissitunicate, short orbicular frequently cylindrical, pedicellate asci. Ascospores are frequently circular in section but narrowing to one end with three or more transverse septa, without longitudinal septa, and mostly with a thick sheath. In recent treatmentsClathrospora,Comoclathris,Diadema,Diademosa, andGraphylliumwere placed in the family. Following molecular and morphological study,Clathrospora,Comoclathris, andDiademosa, are excluded from the family and referred toPleosporaceae.Graphylliumis excluded fromDiademaceae, based on hysterothecium-like ascomata with a longitudinal opening, and tentatively placed inHysteriaceaewith uncertainty; species with hysterothecia have now been accommodated in at least five families. The study accepts onlyDiademain the family. The status ofDiademaceaeas a distinct family, based on the ascomata opening by a flat circular lid, is thought to be doubtful. Fresh collections ofDiademaare needed for epitypification and to obtain sequence data to establish if this is a well-resolved family.