It is surprising that so common a mushroom as Geastrum saccatum seems to lack an accepted common name. It is referred to as the Common Earthstar, the Sessile Earthstar, and the Rounded Earthstar, depending on whose field guide you are consulting. Our Kansas book uses Common Earthstar, which is appropriate because while we do occasionally find other earthstars here, Geastrum saccatum is by far the most prevalent.