The Fine Structure of Ascospore Formation in Pyronema Domesticum

provided by the light microscope. In this report I attempt to show the relationships between the light- and electron-microscopic data, based on evidence obtained from electron micrographs. Light microscopists have provided us with four strikingly different methods of ascospore delimitation. Gjurasin (1893) reported that the divisions of the nuclei in the ascus were karyokinetic and that asters were associated with the division process. In the 8-nucleate stage of the ascus he described the folding of the rays of the aster around the individual nuclei. Harper (1897, 1899, 1900) expanded these observations of nuclear behavior and described free cell-formation, a unique