Dikaryomycota
4. Hyphae can fuse and exchange nuclei and form heterokaryons, particularly dikaryons - necessary stage to sexual reproduction. Dikaryon = cells have 2 haploid nuclei of different origins in a stable state - perpetuated each time cell divides.
Unlike Zygomycetes/ Oomycetes where each meeting of ‘opposite’ nuclei results in 1 sexual spore, hyphal fusion in Dikaryomycota produces many dikaryotic cells and so generates large numbers of sexual spores.