Earthstar

Geastrum, also spelled Geaster, is a genus of puffball-like mushrooms in the family Geastraceae, most of whose species are commonly known as earthstars. The name comes from words for earth and star, describing how the fruiting body's tough outer layer splits at maturity into pointed segments that spread outward across the ground in a star shape. In some species the inner spore sac can lift away from the soil entirely, while in others the outer layer is hygroscopic, opening when damp and closing again as it dries.