Common Ink Cap

Common Ink Cap is a common, edible but potentially poisonous gilled mushroom. It occurs in Europe, Asia, and North America, and it has been found in Australia and South Africa. It is widely distributed in the United States, but it is mostly absent from the deep south, the Great Plains, and the Great Basin. It is common in Minnesota.

Common Ink Cap is found in spring, summer, and fall, in woodlands and gardens, on lawns and roadsides, and around old tree stumps. It appears on the ground in clusters, in dense groups, or sometimes scattered. It obtains its nutrients from already decaying wood (saprobic). It is often attached to buried wood, making it appear to be terrestrial.

When it first appears, the cap is oval and grayish brown to grayish tan, often browner in the center and pale on the margins. The surface has silky fibers (fibrils) attached, remnants of the universal veil. As it ages, the cap spreads out, becoming cone shaped or bell shaped. Mature caps are lead gray, grayish, or grayish brown, convex, 1¼″ to 2⅜″ (3 to 6 cm) high, and up to 4″ (10 cm) in diameter. The surface is smooth. The margins are faintly lined or grooved, and they are usually split or tattered.

The gills are white when young, crowded, and not attached or barely attached to the stalk (free or almost free). They turn gray as the spores mature. Eventually they become black and liquefy (deliquesce), turning to ink.

The stalk is white, hollow, fibrous, 3″ to 6″ (8 to 15 cm) long, and ¼″ to ½″ (6 to 12 mm) thick. It may be narrowed or enlarged at the base, or equal in thickness from top to bottom. There may be grayish to brownish fibrils near the bottom.

The flesh is thin, soft, and pale to grayish. It is edible, but it contains the metabolite coprine. If any amount of alcohol is consumed up to three days before or after eating the mushroom, it will cause “disulfiram syndrome.” The symptoms include facial reddening, nausea, vomiting, malaise, agitation, palpitations, and tingling in limbs. There is no treatment beyond rehydrating after vomiting and reassurance that the symptoms are not fatal.

The spore print is black.

Woodlands, gardens, lawns, roadsides, and around old tree stumps

Spring, summer, and fall

Sources

4, 24, 26, 29, 30, 77.

Common

Common Ink Cap was previously classified as Coprinus atramentarius in the family Agaricaceae. A molecular DNA study published in 2001 showed that most of the species in the genus Coprinus were only distantly related to the type species Coprinus comatus. All but three species were moved to the new family Psathyrellaceae and assigned new genera.

Coprinopsis atramentaria (Coprinus atramentarius) Edible Not mixed with alcohol
The wonderful world of mycology

Coprinopsis atramentaria, ink cap or inky cap, is an edible, sometimes poisonous mushroom
oprinopsis atramentaria, ink cap or inky cap, is an edible, sometimes poisonous mushroom

Common Ink Cap (Coprinopsis atramentaria and the Shaggy Ink Cap (Coprinus comatus)
Wild Food in the UK Ltd

Paul
4/26/2024

Location: St. Cloud, MN