ABSTRACT
Meiosis and premeiotic DNA synthesis were studied in a homothallic isolate of Coprinus patouillardii. Meiosis was demonstrated with cytofluorometry. Premeiotic DNA synthesis occurred after karyogamy, whereas in most fungi it precedes karyogamy. A homothallic C. patouillardii isolate had lower mean nuclear DNA content than a heterothallic isolate in the same species complex. Mechanisms of homothallism in basidiomycetes are discussed.