SUMMARY
Clonal subcultures, obtained by isolating hyphal tips and single spores from a female strain of Dictyuchus monosporus, were found to react (1) as males to the “parental” strain, (2) as males and females when mated to one another, and (3) to be self-fertile (homothallic), in water and on agar. These results raise the question as to whether sex is phenotypically determined in this species. Some strains of Dictyuchus monosporus were found to exhibit homothallic as well as heterothallic behavior. All evidence indicates that sexuality is too variable a factor to be useful for determination of the site of meiosis.