This is a cluster of puffballs, Lycoperdon pyriforme, growing on the side of a decomposing stump in the Rutgers Ecological Preserve. This species of puffball starts as a white or tan fleshy ball but soon dries into a papery sack with a hole on the top. The delicate sack is easily crushed by falling raindrops or animal feet, releasing a cloud of spores (hence the puffball name).

This particular species does not grow more 5 cm or so tall, but much larger puffballs can grow to several inches or even two feet. I have noticed several large puffballs in Highland Park during the summer that look like someone dropped a cantelope in the middle of the grass. This is most likely Scleroderma citrinum, the 'earthball'.

The pictured L. pyriforme is edible when young and white, but supposedly tasteless. You can see in the upper right a slug which has had several bites of each of the puffballs before taking a nap. The larger S. citrinum, however is *poisonous* and should not be eaten.
Photo: Vikas Nanda