Mushroom fungi have no males or females, only compatible partners
Chanterelles, puffballs, bracket fungi, crop-ruining rusts and a yeast that infects people all belong to one fungal division. Their shared signature is a club-shaped cell that fires four spores into the air. And instead of male and female, their threads simply fuse with any partner carrying compatible mating factors.
Basidiomycota, together with the Ascomycota, makes up the Dikarya, often called the higher fungi. The division covers gilled mushrooms, boletes, chanterelles, earthstars, stinkhorns, jelly fungi and polypores, as well as smuts, bunts and rusts that attack plants, mirror yeasts, and Cryptococcus, a yeast that causes human disease. A 2008 estimate counted 16 classes, 177 families, 1,589 genera and 31,515 species.
Most members grow as networks of threads called hyphae. Sexual reproduction ends in the basidium, a club-shaped cell that usually carries four spores on its outside. Some species have given up sex entirely, yet they can still be identified by family resemblance, cell wall chemistry, DNA, or a telltale structure called the clamp connection.
Mating is unusual. Apart from the rusts, compatible partners look identical. Two haploid mycelia fuse their cells, but the nuclei stay separate, producing a dikaryon with paired nuclei in each compartment. Clamp connections help keep those pairs coordinated as the cells divide. Only in the basidium do the nuclei finally merge and undergo meiosis, after which each of the four resulting nuclei moves into its own spore. The spores are shot off ballistically and grow into new single-nucleus mycelia.
Classification has been rebuilt with molecular data. Older schemes split the group into true mushrooms and a second class of jelly, rust and smut fungi; those labels survive only as loose descriptions of growth habit. A 2007 system backed by 67 mycologists recognised three subphyla, with rusts in one, most smuts in another and the mushroom-formers in a third, and a 2020 update listed 19 classes. Some genera still sit unplaced because they are poorly known or unanalysed.
Source: Basidiomycota
