Pisolithus arrhizus

Pisolithus arrhizus (also spelled Pisolithus arhizus) is a widespread earth-ball like fungus, which may in fact be several closely related species. It is known in Australia as the horse dung fungus and in Europe as the Bohemian truffle. This puffball's black viscous gel is used as a natural dye for clothes. Pisolithus arrhizus is a major component in mycorrhizal fungus mixtures that are used in gardening as powerful root stimulators.