They occur in all climatic zones, mainly on land, but also in water, both salty and fresh.
The actual number of mushroom species is very large. It is estimated that there are about 1-1.5 million species of them - four times as many as seed plants.
By 2020, about 148.000 species were described, but about 2000 new ones are described every year - about 90 percent of mushrooms remain unknown.
