The hyphae of these fungi are called dikaryotic , to distinguish them from monokaryotic hyphae. Fungi can also reproduce asexually, usually by forming groups of long hyphae called conidiophores , which resemble a tiny brush. The tips of these conidiophores fragment into hundreds of tiny haploid spores called conidia . Each division of fungi is characterized by special sexual structures unique to that division. Sexual reproduction in zygomycetes results in the formation of zygospores , structures which undergo meiosis and germinate directly into new hyphae.
Ascomycetes reproduce by forming a mushroom-like fruiting body called an ascocarp .
Conjugation, with delayed fusion of nuclei, produces dikaryotic hyphal strands. The tips of these strands form cross walls to isolate a tiny sac or ascus . Ascomycetes are often referred to as sac fungi . The two nuclei in the ascus fuse together into a diploid nucleus, which then undergo meiosis to form four haploid ascospores , which then divide again by mitosis to form eight haploid ascospores . Asexual reproduction is accomplished by conidia bearing conidiospores.