If you have ever noticed a large circle of dead grass surrounded by mushrooms in your lawn, or maybe on your local golf course you are most likely looking at a fairy ring.
The name fairy ring comes from an old folk tale where people believed that circles of mushrooms were a result of fairies dancing in a ring. When talking about lawn care, the best known fairy ring fungus is named Marasmius oreades. The body of this fungus is contained underground and it grows in an outward circle. As it grows, the mycelium uses up all of the nutrients in the soil, causing the grass to turn brown. Mushrooms will then sprout up just behind the line of the mycelium.
Fairy rings made by fungi like Marasmius oreades are called “free” rings. They will continue to grow outward until a barrier is reached. Sometimes the barrier is another fairy ring! Rings can grow into each other’s territory and die as each reaches the other’s “dead zone.” One ring formed in France by the fungus Clitocybe geotropa is almost a half mile in diameter. This ring is thought to be 700 years old.Tweet