Western Giant Puffball

A number of potentially poisonous, white mushrooms are similar in appearance when they are in their immature button stage and lack a visible stem. Button stage mushrooms differ in that they are smaller (under 4 cm broad) and exhibit the faint outline of gills or other structures when cut in half, rather than having undifferentiated flesh. The edible and similar-looking Calbovista subsculpta differs in that it is smaller (up to 15 cm broad), has pyramidal warts that are broader and less prominent, and has a well-developed base below the gleba, called a subgleba. The edible but less common Calvatia gigantea is similar in size and color but differs most obviously in that the surface is smooth and free of raised warts.