Coprinus comatus, the shaggy ink cap, lawyer's wig, or shaggy mane, is a common fungus often seen growing on lawns, along gravel roads and waste areas. The young fruit bodies first appear as white cylinders emerging from the ground, then the bell-shaped caps open out. The caps are white, and covered with scales—this is the origin of the common names of the fungus. The gills beneath the cap are white, then pink, then turn black and secrete a black liquid filled with spores (hence the “ink cap” name). This mushroom is unusual because it will turn black and dissolve itself in a matter of hours after being picked or depositing spores.
When young it is an excellent edible mushroom provided that it is eaten soon after being collected (it keeps very badly because of the autodigestion of its gills and cap). If long-term storage is desired, sauteing or simmering until done will allow the mushrooms to be stored in a refrigerator for several days or frozen. Processing must be done whether for eating or storage within four to six hours of harvest to prevent undesirable changes to the mushroom. The species is cultivated in China as food.
The shaggy ink cap is easily recognizable from its almost cylindical cap which initially covers most of its stem. The cap is mostly white with shaggy scales, which are more pale brown at the apex. The free gills change rapidly from white to pink, then to black. It is deliquescent. The stipe has a loose ring and measures 10-37 cm high by 1-2.5 cm diameter. Microscopically it lacks pleurocystidia. The spore print is black-brown and the spores measure 10–13 × 6.5–8 µm. The flesh is white and the taste mild.
It grows in groups in places which are often unexpected, such as green areas in towns. It occurs widely in grasslands and meadows in Europe and North America. It appears to have been introduced to Australia, New Zealand and Iceland.
The young mushrooms, before the gills start to turn black, are edible. It can sometimes be used in mushroom soup with parasol mushroom.
The agent responsible for unpleasant symptoms when consumed with alcohol, coprine, which is found in Coprinopsis atramentaria, has not been isolated from Coprinopsis comatus.