Calvatia gigantea, commonly known as the giant puffball, is a puffball mushroom commonly found in meadows, fields, and deciduous forests usually in late summer and autumn. It is found in temperate areas throughout the world,Most giant puffballs grow to be 10 to 70 centimetres (3.9 to 27.6 in) in diameter, although occasionally some can reach diameters up to 150 centimetres (59 in) and weights of 20 kilograms (44 lb). The inside of mature Giant puffballs is greenish brown, whereas the interior of immature puffballs is white. The large white mushrooms are edible when young.
The fruiting body of a puffball mushroom will develop within the period of a few weeks and soon begin to decompose and rot, at which point it is dangerous to eat. Unlike most mushrooms, all the spores of the giant puffball are created inside the fruiting body; large specimens can easily contain several trillion spores. Spores are yellowish, smooth, and 3 to 5 micrometres (0.00012 to 0.00020 in) in size.
The classification of this species has been revised in recent years, as the formerly recognized class Gasteromycetes, which included all puffballs, has been found to be polyphyletic. Some authors place the giant puffball and other members of genus Calvatia in order Agaricales. Also, the species has in the past been placed in two other genera, Lycoperdon and Langermannia. However, the current view is that the Giant Puffball is Calvatia.