fairy ringfairy ring
a circle of mushrooms often seen on grassy ground, originating from one initial mycelium and often accompanied by a circle of darker grass: so called because formerly thought to have been made by the dancing of fairies
A circle of mushrooms in a grassy area, marking the periphery of perennial underground mycelial growth.
Origin of fairy ringFrom the belief that it is a dancing place for fairies
(plural fairy rings)