Perithecia line the periphery of the stroma and so are able to produce ostioles on the stroma surface, through which ascospores will be dispersed. Prepared slide of longitudinal section of Xylaria , at a higher magnification. The series Discomycetes is characterized by the formation of an ascocarp called an apothecium. Whatever their shape may be, the asci form a hymenium that is usually, entirely exposed at maturity. The asci are unitunicate and forcibly eject the ascospores.
Paraphyses are generally present in apothecia.
Sarcoscypha coccinea , a typical cup-shaped apothecium. Sarcoscypha mesocyatha is more flattened and has a dish or saucer-shaped apothecium. The morphology of Morchella esculenta , as well as other species of morels, is far different than the two examples above. The ridges that can be seen on the surface are sterile. Asci and ascospores are found only in the sunken areas of this apotheciuim.