Fairy Rings, Toadstools, Mushrooms - Mushrooms in lawns are common especially during rainy weather. They live off decaying organic matter in the soil, often decaying tree roots and are not harmful to the lawn. They will naturally disappear with age or they may be collected and composted, knocked down with a rake or hoe or mowed over with mower. Mushrooms should never be collected and eaten unless you are expert in their identification. To many gardeners, poisonous mushrooms can look very similar to edible ones. Don’t take a chance. Fairy rings are the fruiting bodies of fungi growing on decaying organic matter. The white caps look like golf balls when young but expand to 4’-8” in diameter at maturity. Usually appear in lawns in summer after rainy periods. Caps are white at first, then turn gray-green and have distinctive green spores, reddish brown “scales” on the cap and a ring on the smooth stalk. Fairy rings usually grow in soil where wood of dead roots, lumber or old stumps are decaying. These organisms are toxic and known for their tendency to collect heavy metals from the air and soil.