Calvatia bovista
Introduction '''''Calvatia bovista''''' is a species of ''Calvatia'' mushroom, the second largest Calvatia in North America. As with other ''Calvatia'' mushrooms, it is edible when young, and it is used in medicine.
Description The fruiting body is  high and  wide, round on top with a wide stemlike sterile base, often half the height of the fruiting body. Spores are 4-6μm, round, minutely warted or spiny. It is seen in pastures, open woods, etc., fairly common.
References
External links *  ''Calvatia bovista'' at Mushroomobserver.org.