Fairy rings are caused by fungi belonging to which class?

Fairy rings are indeed caused by fungi from the Basidiomycete class. This group of fungi is characterized by their production of fruiting bodies, commonly known as mushrooms, which emerge from the mycelium that spreads underground. The fairy ring itself is a circular pattern of fungus that can appear in grassy areas, often attributed to the way Basidiomycetes grow and expand outward from a central point.

As they colonize the soil, these fungi decompose organic matter and can alter the growth of the surrounding grass, creating a distinctive ring shape. The fairy ring phenomenon occurs as the mycelium grows in a circular pattern, with the outer edges producing mushrooms, while the inner area becomes depleted of nutrients due to the fungal growth.

The other classes of fungi listed do not produce fairy rings in the same manner. Ascomycetes are known for their unique reproductive structures called asci, while Oomycetes, often called water molds, and Chytridiomycetes, primarily aquatic fungi, do not typically form such patterns in terrestrial environments. Thus, the association of fairy rings with the Basidiomycete class is well established in mycology.