Electron microscopy of the septa in hyphae of Dipodascus species showed a narrow, central pore in D. uninucleatus and plasmodesmata in D. aggregatus, Ascospores in D. uninucleatus are small, oval, or reniform; in D. aggregatus they are much bigger with a wall which is first narrow and later expands considerably. The description of the spores of the type species, D. albidus, of which no strains were available for examination, agrees with that of D. aggregatus. Apart from the features mentioned above, D. uninucleatus differs from D. albidus and D. aggregatus in other important characteristics, such as the method of gametangia formation and the structure of the cell wall.