The ultrastructure of the ascus and the ascospore wall of Eleutherascus lectardii, E. tuberculatus, E. peruvianus, Ascodesmis nigricans, and A. microscopica is studied and compared. Especially the development of the primary and the secondary spore walls is exactly the same in Eleutherascus and Ascodesmis. Eleutherascus is placed as an extremely simple fungus in the Ascodesmidaceae (Pezizales).