A phenomenon of ascospore death was observed in a number of Schizosaccharomyces pombe interstrain hybrids. Meiotic recombination of the control parental auxotrophic markers was, however, observed in a random ascospore analysis. Genetic and molecular biological data indicated existence of at least geographical divergence of the genomes in Sch. pombe populations. Classification of the genus, species, and varieties of these yeasts is discussed.