Abstract
After a short review of the historical development of the problem of cytoplasmic inheritance, the principles for the proof of cytoplasmic inheritance were discussed. At present the proof can be based on the maternal transmission of plasmagenes, on the missing of mendelian segregation and on the possibility of a segregation during ontogenetic development. In the following the most important possibilities for errors and their refutation onEpilobium were discussed: elimination of genotypes , abnormal cytology , maternal aftereffects , predetermination , nuclear produced plasmagenes and transmission of parasites or symbionts as virus . At the end the principles for the distinction between different cytoplasmic constituents were discussed