#pixie ring

https://en.m.wikipedia.org/wiki/Fairy_ring

A fairy ring, also known as fairy circle, elf circle, elf ring[1] or pixie ring, is a naturally occurring ring or arc of mushrooms.[2] They are found mainly in forested areas, but also appear in grasslands[3] or rangelands. Fairy rings are detectable by sporocarps (fungal spore pods) in rings or arcs, as well as by a necrotic zone (dead grass), or a ring of dark green grass. Fungus mycelium is present in the ring or arc underneath. The rings may grow to over 10 metres (33 ft) in diameter, and they become stable over time as the fungus grows and seeks food underground.

Known as St. George’s Mushroom in the UK, Vårmousseron in Scandinavia or by its Latin name, Calocybe gambosa, this delectable foraged delight grows in fields, by the side of roads, the edge of woodland and on patches of grass throughout Europe, North America, Russia and Japan.