 A discarded hypothesis held that a second karyogamy event occurred in the ascogonium prior to ascogeny, resulting in a tetraploid nucleus which divided into four diploid nuclei by meiosis and then into eight haploid nuclei by a supposed process called brachymeiosis, but this hypothesis was disproven in the 1950s.From the fertilized ascogonium, "dinucleate" hyphae emerge in which each cell contains two nuclei.These hyphae are called "ascogenous" or fertile hyphae.