Scanning ultrastructural ontogeny of paragymnohymenial apothecia in the operculate discomycete Peziza quelepidotia

Morphogenesis of apothecia in Peziza quelepidotia Korf and O'Donnell, a homothallic operculate discomycete (Pezizales, Pezizaceae), was investigated with the scanning electron microscope from ontogeny of the ascogonial coils through spore discharge. Since the incipient paraphyses are never completely closed by the overarching ectal excipular margin, hymenial development is classified as paragymnohymenial. At the late mesohymenial phase, operculate asci protrude as much as 25–35% of their length above the level of the paraphyses. Patches of hyphoid processes in the hymenium may function to preserve the hymenial compactness in the late-mesohymenial to telohymenial ascocarps. The microanatomy of the excipula, as revealed by median longitudinally sectioned ascocarps, is characteristic for the genus. In addition, an abberant, bicupulate ascocarp is figured.