A puffball is a member of any of a number of groups of fungus in the division Basidiomycota. Puffballs are common in meadows and woods and on heaths or lawns. When young, their fruiting bodies are whitish spheres, sometimes with short stalks, and are fleshy in texture. If cut across in this state, they show a compact rind enclosing a loose tissue, in the interspaces of which the spores are developed; as the fungus matures it changes to yellowish-brown and brown. When ripe, the rind tears at the apex and the spores escape through the aperture when any pressure is applied to the ball. Certain white and fleshy puffballs are edible, while others are poisonous. The giant puffball, Calvatia gigantea, reaches a foot (30 cm) or more in diameter, and is difficult to mistake for any other fungus.