mica cap, shiny cap

Coprinellus micaceus is a common species of fungus in the family Psathyrellaceae with a cosmopolitan distribution. The fruit bodies of the saprobe typically grow in clusters on or near rotting hardwood tree stumps or underground tree roots. Depending on their stage of development, the tawny-brown mushroom caps may range in shape from oval to bell-shaped to convex, and reach diameters up to 3 cm (1.2 in). The caps, marked with fine radial grooves that extend nearly to the center, rest atop whitish stems up to 10 cm (3.9 in) long. In young specimens, the entire cap surface is coated with a fine layer of reflective mica-like cells that provide the inspiration for both the mushroom's species name and the common names mica cap, shiny cap, and glistening inky cap. Although small and with thin flesh, the mushrooms are usually bountiful, as they typically grow in dense clusters. A few hours after collection, the gills will begin to slowly dissolve into a black, inky, spore-laden liquid—an enzymatic process called autodigestion or deliquescence. The fruit bodies are edible before the gills blacken and dissolve, and cooking will stop the autodigestion process.
Coprinellus micaceus is an edible species,[19][35] and cooking inactivates the enzymes that cause autodigestion or deliquescence—a process that can begin as soon as one hour after collection.[36] It is considered ideal for omelettes,[22] and as a flavor for sauces,[14] although it is "a very delicate species easily spoiled by overcooking".[37] The fungus also appeals to fruit flies of the genus Drosophila, who frequently use the fruit bodies as hosts for larvae production.[38][39]

A study of the mineral contents of various edible mushrooms found that C. micaceus contained the highest concentration of potassium in the 34 species tested, close to half a gram of potassium per kilogram of mushroom.[40] Because the species can bioaccumulate detrimental heavy metals like lead and cadmium, it has been advised to restrict consumption of specimens collected from roadsides or other collection sites that may be exposed to or contain pollutants.[41