Fairy Rings

Have you ever gone walking in the woods and found a "fairy ring" of mushrooms? What causes the toadstools to grow in this circular pattern?

The fungi you can see is actually the outer ring of a mycelium that's growing underground. A spore lands, germinates and grows outwards in every direction. You'll also often see that the grass around the mushrooms grows better, because the mycelium is breaking down the organic matter in the soil, making it more accessible for both the mycelium and the surrounding plants. These rings can grow up to 10m in diameter.