Abstract
One area of genetics particularly dominated by German-speaking geneticists (Brücher, Correns, Lehmann, Michaelis, Oehlkers, Renner, von Wettstein) during the interwar period was research in the field of cytoplasmic inheritance (Plasmon-Theory). The controversy between the botanists Lehmann (Tübingen) and Brücher (Jena, Tübingen) about the function of “supressor genes” in Epilobium cell division was central to debates about cytoplasmic inheritance. The failure of Brücher, Michaelis and Oehlkers to replicate Lehmann's Epilobium experiments ultimately forced Lehmann to admit his error.