Coprinellus micaceus - "Glistening Inky Cap"

Young Coprinellus micaceus specimens at base of maple tree

Mature Coprinellus micaceus cluster at base of maple tree

Spore print

Name: Coprinellus micaceus (formerly known as Coprinus micaceus)
Spore Color: dark brown or black (not jet black)
Location Found: around base of maple tree in yard
Special Characteristics:

• after maturation or hours after harvesting, the gills will dissolve into an inky, black goo - a process known as autodigestion
• usually grows in clusters
• the caps of young specimens are covered with shiny "mica-like" cells, but usually are washed off/rubbed off with age

Edibility: Only edible before the autodigestion process begins. Boiling the mushrooms stops this process completely. They are recommended to use in omelettes and have a soft flavor that is easily overpowered.

Extra: Two very important things to note about this species is its situationally toxic lookalike, Coprinopsis atramentaria, and its mineral content. 

Coprinopsis atramentaria and Coprinellus micaceus both look similar, with the former having a more grey/tan-colored cap. The latter is much more tan, almost orange-tinged at times. It's also important to note that Coprinopsis atramentaria does not have the "mica-like" cells on its cap. Both are usually found in clusters and will turn into an inky black mess after maturation. They both have the exact same color spore print as well, which definitely complicates things further.

Though they can look similar, this mistake in identification can mean life or death in one certain situation: if the person who devours them has been drinking. While Coprinellus micaceus is safe to eat under any condition, Coprinopsis atramentaria contains a compound called coprine which in basic terms will give the eater an "instant hangover." While this may seem innocent enough, the symptoms can also include nausea, vomiting, heart palpitations, and most dangerously, heart attack and death. The symptoms are proportionate to the amount of alcohol consumed. If consumption is suspected, the affected shouldn't drink for three days.

Another important thing to note is its mineral content. Coprinellus micaceus is well known for its high potassium levels, making it quite healthy. Unfortunately it also has a tendency to absorb heavy metals like lead and cadmium, making the location from where you harvest a very important factor in judging its edibility. It's recommended not to consume any mushrooms from roadsides or industrial areas for this precise reason.