Mica Cap

Coprinellus micaceus (formerly Coprinus micaceus)


Photo of mica cap cluster, bell-shaped, brown, capped mushrooms
Mica cap cluster
Lisa K. Suits
Other Common Name
Common Inky



Bell-shaped, tawny brown, radially lined cap; inky gills. Grows in clusters around stumps or on wood debris. April–October. Cap egg-shaped, becoming bell-shaped; tawny brown, darkening with age; covered with shiny, micalike granules when young; with age, cap and gills become inky and liquefy. Gills broad; spacing close; white, becoming dark brown, then inky black; gills attached. Stalk thick; white, discoloring to buff; smooth, sometimes like felt; fragile, hollow. Universal veil leaves shiny, micalike granules on cap when young, but these disappear quickly. Spore print dark brown to black. Spores magnified are elliptical, smooth, with small pore at tip.

Lookalikes: The alcohol inky (Coprinopsis atramentaria) is fleshier and grayish.


Cap Width: ½–2 inches; stalk length: 1–3 inches; stalk width: 1⁄8–¼ inch.

Mica Cap (Common Inky)

Mica Cap (Common Inky)
Mica Cap (Common Inky)
Mica Cap (Common Inky) in Putnam County
Habitat and conservation

Grows in clusters around stumps or on wood debris, occasionally on buried wood (causing them to look like they're growing from the soil).

image of Mica Cap Common Inky distribution map
Distribution in Missouri



Edible, when young and fresh, and before the cap begins to dissolve into inky liquid (deliquesce). Don't try to save these for later in the refrigerator; it won't keep them from liquefying. Cook your mica caps soon after collecting.

Life cycle

Mushrooms exist most of the time underground or within rotting logs as a network of cells (mycelium) connected to whatever it is they take nourishment from, in this case, rotting wood. When ready to reproduce, the mycelium sends up the mushroom, which is the reproductive structure. Spores are produced in the gills and are released to begin new mycelia elsewhere. In inky caps, the spores are distributed when the cap liquefies.

Human connections

Coprinoids or inky caps have black spores that turn wet and “inky” with age. Eventually the caps will autodigest (dissolve into nothing). A black ink can be made by boiling the dark, liquifying caps with a little water and cloves.

Ecosystem connections

This is one of the many fungus species that live on decaying plant materials. It and other such saprobic fungi play an incredibly important role in breaking down the tough materials plants are made of and returning those nutrients to the soil.