Mushroom is a small white ball, 1 to 2.5 inches across, sometimes with a short thick stalk. The ball is studded with short conical spines (the "gems"). The ball becomes a sac filled with spores. When the spores mature the sac develops a slit at the top and the spores are expelled when wind, animals, or rain disturb the sac. By that point the sac will usually have turned brown and the spines will have fallen off, leaving scars. Occurs singly or in groups on the ground in the summer and fall.

A widespread fungus. Usually in forests, but also in open areas, along roadsides and in suburban lawns. Common in Wildwood, in open areas, including near the Outdoor Classroom.

The gems are the best identification key. When old it can be distinguished from pear-shaped puffball by its habit of growing on the ground, not on wood.