Agaricus campestris

Also known as Meadow Mushroom, Field Mushroom, Pink Bottom

Field mushrooms emerge rapidly in lush pastures and grassy lawns after autumn rains, often forming expanding fairy rings across open meadows. Caps open from convex cushions into broad, flat discs, revealing soft pink gills that darken to deep chocolate brown as spores mature. Beneath the soil, an extensive network of fungal threads decomposes dead plant matter and enriches the surrounding soil.