A group of fungi that reproduce through asexual spores and sexually-produced spores
Fungi are heterotrophic eukaryotes that are usually filamentous, devoid of chlorophyll, with chitinous cell wall, and produces spores. Most species of fungi live as multicellular organism. They form filaments called hyphae, which form a mycelium. Other fungal species live as single-celled. They reproduce by means of spores. The old classification scheme of fungi is based on their mode of reproduction. Accordingly, those that reproduce through asexual spores and sexually-produced spores are called perfect fungi whereas fungi that reproduce only by asexual spores are called imperfect fungi.
Asexual reproduction is mediated by conidia (vegetative spores) or by mycelial fragmentation. This mode of reproduction makes fungi to spread rather easily than by sexual reproduction. A fragment of the mycelia can grow into a separate mycelium.
Sexual reproduction is carried out by the fusion of the hyphae of compatible haploid mating types. Those that mate with another of the compatible type are described heterothallic whereas those that mate with themselves are homothallic.
In many ascomycetes and basidiomycetes, there is a dikaryotic phase wherein the nuclei from the two parents do not combine immediately after the fusion.
In glomeromycetes, the haploid hyphae of two fungi merge and form a gametangium, which then develops into a zygospore. The zygospore, in turn, germinates and undergoes meiosis, generating new haploid hyphae.