Explanation:

Sexual reproduction takes place by the formation of antheridium and ascogonium.Mating in Ascomycota. As it approaches a mate, a haploid sac fungus develops one of two complementary organs, a "female" ascogonium or a "male" antheridium. These organs resemble gametangia except that they contain only nuclei. ... A dikaryote grows from the ascogonium, and karyogamy occurs in the fruiting body