fairy ring

The idea of a ring where fairies danced was a traditional explanation for the fungal phenomenon before it was understood.

fairy ring (plural fairy rings)

1. (mycology, botany) A ring of fungi marking the periphery of the perennial underground growth of the mycelium.

   Synonyms: elf circle, fairy circle, pixie ring

   • 1821, Edward Polehampton, chapter VIII, in The Gallery of Nature and Art: Or, A Tour Through Creation and Science, volume 5, page 316:

     This curious phenomenon has been differently accounted for. The following is Mr. Nicholson's description and explanation: "the appearance in the grass, says he, commonly called Fairy Rings, is well known. It consists either of a ring of grass of more luxuriant vegetation than the rest, or a kind of circular path in which the vegetation is more defective than elsewhere. It appears to be pretty well ascertained that the latter state precedes the former. […]

   • 2012, Juliana Regina Delion, Heart Attack!: Shadows on the Eve of Tomorrow, Xlibris Corporation (→ISBN), page 18

     So writing it down and reading it later, I realized somehow my subconscious was giving me a warning of things to come. In the dream I woke up at the height of the full moon in my garden. I didn't realize that in my drunken stupor I had fallen asleep amidst a fairy ring. A fairy ring is a bunch of mushrooms growing in a circle. I often see them growing on lawns. Legend has it that if one gets caught in this circle on a full moon, the fairies will take him or her captive and do as they please.

2. (mythology) A mythical place where fairies are thought to congregate in a ring.

• fairy ring on Wikipedia.Wikipedia

• rarifying