Abstract
The results of selfing and intercrossing two strains of the flax rust fungus Melampsora lini indicate that this species does not possess a simple(+) and() mating system. Instead, the data are consistent with the assumption that the genetic control of mating type in Melampsora lini is similar to that in the mushroom Schizophyllum commune, in which mating type is determined by two factors, each of which is controlled by two linked loci.