Ultrastructure of the ascospore wall in Pezizales (Ascomycetes)—IV. Morchellaceae, Helvellaceae, Rhizinaceae, Thelebolaceae, and Sarcoscyphaceae. General discussion

The development of wall layers and ornamentation of ascospores, plus specialized plasmic structures, are studied with the electron microscope in members of the Morchellaceae, Helvellaceae, Rhizinaceae, Thelebolaceae, and Sarcoscyphaceae; additional results in the Pyronemataceae are given. The findings are compared with those of former studies (Merkus, 1973, 1974, 1975). A general discussion on the origin and development of the different structures concludes the series. A classification based upon species representing typical developments of all the species of the four studies is made.