Shaggy Ink Cap
Genus Coprinus Pers. 1797
Species Coprinus comatus (O.F. Müll.) Pers.
Native to North America, Europe, and Asia
Shaggy Inky Cap
Found on lawns, wood chips, or hard-packed ground, summer and fall, alone or in clusters
Edible if gathered when young and eaten immediately
[Not to be confused with the Common Ink Cap, which when preceded or followed by the consumption of alcohol produces the granddaddy of all hangovers.]
Gills liquefy to produce "ink" that may actually be used as writing ink. Liquefying gills allow for effective dispersal of spores. Gills liquefy from the bottom up, the cap peeling up and away, changing shape from oval to bell-like to flat, to expose the spores to wind currents.
How to make ink