Shaggy ink cap

Description

The shaggy ink cap is a tall, slender mushroom with a white, cylindrical cap covered with fibrous scales, with a brownish tip. The young fruiting body looks like a white column growing out of the ground, and the stem is white, hollow, with a movable ring. The gills turn pink with age, then black, and the whole cap dissolves into a black liquid.

It grows from April to November on lawns, meadows, verges, in gardens and on ruderal land, less often in forests, often in groups. In Poland it is very common.

It can be confused with the common ink cap (grey, smooth cap), which causes poisoning when eaten with alcohol.

Identification features

Cap

Height 5–10 cm (descriptions also give a width of 4–8 cm, height 6–20 cm). Cylindrical when young, almost completely enclosing the stem, later bell-shaped. White, fibrous-scaly; the apex ochre to light brown and bare. In a mature fruiting body the margin splits radially and lifts, and the cap together with the gills undergoes autolysis (dissolves) into a black liquid containing spores.

Hymenophore (underside of the cap)

Gills free, crowded and thin; white at first, quickly turning pink, finally black and dissolving.

Stem

Height 10–20 cm (descriptions also give 6–40 cm), thickness 0.8–2 cm (descriptions also give 1–2.5 cm). Cylindrical, hollow, whitish, smooth, breaks easily away from the cap, slightly rooting. Ring movable, loose, usually in the lower part of the stem.

Flesh

White, thin and brittle in the cap, soft and fibrous in the stem. Taste mild, smell pleasant but indistinct. Tasting an unknown mushroom is not recommended.

Spore print and spores

Spore print black (according to some descriptions blackish-brown). Spores elliptical, smooth. Size 10–15 × 6–8 µm (descriptions give different ranges).

Habitat and distribution

Ecology. A terrestrial saprotroph. A nematophagous fungus, able to kill and digest nematodes (Panagrellus redivivus, Meloidogyne arenaria). Grows on lawns, meadows, pastures, roadsides, rubbish dumps and other ruderal habitats, also in forests and near people, often in groups.

Distribution. On all continents except Africa and Antarctica; very common in Poland. Probably introduced to Australia, New Zealand and Iceland. Not legally protected in Poland; it is on the list of mushrooms approved for sale (Ministry of Health, item 9).

Fruiting. From April to November.

What can it be confused with?

• Coprinopsis atramentaria (common ink cap) — Cap smooth and grey, not white-scaly. It contains coprine — in combination with alcohol (before and after a meal) it causes poisoning.
• Coprinopsis picacea (magpie fungus) — Poisonous and possible to confuse; detailed differences — no data.
• Chlorophyllum molybdites — In America it is responsible for most poisonings because of its similarity to the shaggy ink cap; it does not occur in Poland; detailed differences — no data.
• Podaxis pistillaris — Similar; detailed differences — no data.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The fruiting body undergoes autolysis within a few hours of collecting or of releasing its spores; this is where the name "ink cap" comes from.
• In the past some atlases listed it as poisonous with alcohol; studies have shown that this species does not contain such compounds (in the common ink cap it is coprine).
• The species name comatus comes from the Latin coma — "hair", i.e. "shaggy".
• It is the type species of the genus Coprinus; after DNA analyses the former, broad genus was divided between two families (Agaricaceae and Psathyrellaceae).
• In 1981 Australia Post issued a stamp with it.