The life cycle of basidiomycetes begins with haploid basidiospores that germinate to form mycelia of two mating types ($+$ and $-$). During plasmogamy, the fusion of these mating types results in the formation of a dikaryotic mycelium. Through mitosis, this mycelium develops into a fruiting body called a basidiocarp, which bears basidia within its gills. Within the basidia, karyogamy occurs to produce diploid zygotes, which then undergo meiosis to form four haploid nuclei. Cell division subsequently produces four haploid basidiospores that are dispersed to germinate into new mycelia.