Common Ink Cap vs Magpie Inkcap
Coprinopsis atramentaria compared with Coprinopsis picacea — how to tell them apart in the field.
How to Tell Them Apart
Much more common, lacks the white patches. Cap is uniformly gray-brown. Grows in clusters at the base of stumps, not singly in beech litter. Contains coprine, which causes illness when combined with alcohol.
Side-by-Side Identification
| Trait | Common Ink Cap | Magpie Inkcap |
|---|---|---|
| Cap | 4-8 cm across, 3-8 cm tall. Starts as a smooth, egg-shaped grey-brown bell. Surface has fine radial grooves and sometimes tiny scales near the top. As it ages, the edges curl up and begin dissolving into black ink. Young caps are the only ones worth looking at — once the ink starts flowing, it's past its prime. | 5-8 cm tall when closed, expanding to 6-10 cm across when open. Initially egg-shaped to cylindrical, expanding to conical or bell-shaped before deliquescing. Black to very dark brown, covered with large, irregular white patches of veil remnants. Surface between patches is smooth. Flesh is thin and fragile. |
| Gills | Packed tightly together, initially white, turning pink, then black as spores mature. Eventually liquefy into ink from the cap edge inward. Free from the stem. | Free (not attached to stem). White when very young, rapidly darkening to gray, then black, before dissolving into inky black liquid (deliquescence). Crowded and very thin. |
| Stem | 5-15 cm tall, white, hollow, smooth with a slight silky sheen. Has a faint ring zone near the base but no persistent ring. Fibrous and snaps cleanly. | 10-25 cm tall, 1-2 cm thick. White, smooth to finely fibrillose, hollow. Tall and slender, often slightly wider at the base. No ring. Surface is smooth and white throughout. |
| Spore print | Black — very dark, almost jet black. | Black. Easily obtained by catching the inky liquid that drips from the dissolving cap. |
| Odor | Mild and pleasant when young. Nothing remarkable. | Unpleasant when mature, described as chemical or tar-like by some observers. Young specimens have a milder, nondescript odor. |
| Habitat | Loves disturbed ground — gardens, roadsides, paths, compost heaps, and anywhere with buried wood or tree roots. Often appears in dense clusters near stumps or along the edges of lawns. Saprotrophic, feeding on decaying wood underground. | Saprotrophic on buried wood and rich leaf litter in deciduous woodlands. Strongly associated with beech (Fagus sylvatica) in Europe. Also found under other hardwoods including oak and elm. Prefers deep, undisturbed leaf litter on calcareous (chalky or limy) soils. |
| Season | Spring through late autumn. Most common in September and October in temperate regions. Can fruit after heavy rain almost any time of year in mild climates. | Autumn, typically September through November. Peak fruiting in October in most of its European range. Fruits after sustained autumn rains when soil temperatures begin to cool. |
Found one of these in the wild? Don't rely on memory — identify it from a photo with Orangutany and check it against both species before you touch it.