The Basidiomycota is a large group of fungi including mushrooms, puffballs, jelly fungi, smuts, rusts etc. Most species are terrestrial, but some are aquatic. They are saprobic or symbiotic (e.g. rusts, smuts, lichens, ectomycorrhizal fungi). Some parasitic species seriously damage to plants and animals. There are many edible fungi in the Basidiomycota (e.g. mushrooms, jelly fungi) and some species are cultivated. The basidiomycetes are also important as sources for usuful material (e.g. toxins, enzymes, pigments).

Although some basidiomycetes are unicellular (e.g. Cryptococcus), most basidiomycetes form hyphae. Some species form macroscopic fruiting body composed of hyphae. Thalli are basically uninucleate haploid, but binucleate thalli are usually formed via fusion of cells/hyphae. The dikaryotic hyphae grow and maintain binucleate condition by usually the formation of clamp connections. In the sexual reproduction, the binucleate thalli form basidium in which karyogamy and meiosis occur. The haploid extracellular basidiospores are produced on basidium. Many species produce basidia on macroscopic fruiting bodies (e.g. mushrooms), but basidia can also be formed from single cells (e.g. yeasts). Some basidiomycetes produce asexual spores and lack sexual reproduction and formation of basidiospores.