 Coprinopsis atramentaria , commonly known as the common ink cap or inky cap , is an edible ( but sometimes poisonous , see below ) mushroom found in Europe and North America . Previously known as Coprinus atramentarius , it is the second best known ink cap and previous member of the genus Coprinus after C. <unk> . It is a widespread and common fungus found throughout the northern hemisphere . Clumps of mushrooms arise after rain from spring to autumn , commonly in urban and disturbed habitats such as vacant lots and lawns , as well as grassy areas . The grey @-@ brown cap is initially bell @-@ shaped before opening , after which , it flattens and disintegrates . The flesh is thin and the taste mild . It can be eaten but is poisonous when consumed with alcohol – hence another common name , tippler 's bane . 
