The life-cycle and nuclear conditions in Zygomycetes present still problems in spite of more than 100 years research. The process of conjugation was discovered as early as 1820 by Ehrenberg. In two papers from 1984 Dangeard and Leger made important observations on nuclear behaviour in the zygospores. Blakeslee (1904, 1906) examined different species, with the aim of establishing them as experimental material and to develop a field of fungal genetics. Unfortunately, nuclear behav iour both during formation, dormancy and germination of the zygospores remained obscure. Different problems arose, involving absence of regular germination of the zygospores and not at least, problems of staining and studying the tiny nuclei.