Fruiting body buried to epigeous, 1.5-5 cm broad, globose, at maturity often slightly flattened to cushion-shaped, the base pinched or folded, attached to the substrate via a tuft of mycelium, the latter sometimes aggregated into a pseudostipe; peridium when young, 1-1.5 mm thick, tough, smooth, becoming finely cracked or areolate, especially the upper portion; spores released via irregular splitting or "cratering" of the apex; color: white, soon tinged vinaceous to pinkish-brown or ochraceous-brown, bruising darker brown where handled or injured; gleba white turning purple-black, firm-textured, with interspersed white mycelium, in age, dull brown; odor: of mushrooms; taste: mild.
Spores 8-10 x 8.5-10 µm, nearly round, spinose; spores dull brown.
Solitary or in small groups in sparse grass, gardens, along paths, and under a variety of trees; fruiting during the summer in watered areas and after the fall rains.
Toxic, to be avoided.
Like other members of the genus Scleroderma, S. cepa has a thick, tough peridium. This character along with a firm, dark-purple gleba that is never soft, or semi-liquid, helps to separate it from members of the "true puffballs," i.e. Calvatia, Lycoperdon, etc. The common name "earthball" comes from the tendency of this and several other Sclerodermas to be only partially erumpent. Many are found by troweling in areas where a single fruiting body has been exposed. Scleroderma cepa is characterized by a smooth, white peridium that becomes pinkish-brown, to ochraceous-brown, dark brown where handled or in age. The surface is then often cracked or areolate, but not with raised warts as is the case in Scleroderma citrinum which can be further distinguished by reticulate rather than spiny spores.