Coprinellus impatiens (Fr.) J.E. Lange

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Psathyrellaceae

Coprinellus impatiens

Similar to the Fairy Inkcap (also known as the Trooping Inkcap), Coprinellus disseminatus, but larger and with distinctive ‘piano key’ grooves almost to the cap centre, this rather uncommon (in Britain and Ireland) mushroom occurs in small groups on deciduous broadleaf litter; it is most often seen under Beech trees on chalky soil. (The specimens pictured here were among bark fragments and accumulated leaf litter that the wind had swept into a shallow depression beneath an old spreading Beech tree.)


Rather uncommon in most parts of Britain and Ireland, this little inkcap occurs mainly in lime-rich regions throughout mainland Europe and in parts of North America

Taxonomic history

This inkcap mushroom was first described scientifically in 1821 by great Swedish mycologist Elias Magnus Fries and given the name Agaricus impatiens. The French mycologist Lucien Quelet later transferred it to the now defunct genus Coprinarius and shortly after, in 1888, to the genus Coprinus. Significantly, in 1938 the Danish mycologist Jakob Emanuel Lange (1864 - 1941), redefined this species as Coprinellus impatiens, within the family Psathyrellaceae, but despite this many mycologists (and most published field guides) continued to refer to this inkcap as Coprinus impatiens until 2001 when, as a result of molecular (DNA) analysis, the Coprinus genus was shown to contain groups of fungi with only distant relationships to one another, and the earlier Coprinus group was dismantled with the Glistening Inkcap being moved into the genus Coprinellus. (Coprinus comatus, the Shaggy Inkcap, plus three other rare fungi are all that remains in the formerly large Coprinus genus.)

Synonyms of Coprinellus impatiens include Agaricus impatiens Fr., Coprinus impatiens (Fr.) Quel., Psathyrella impatiens (Fr.) Kühner, and Pseudocoprinus impatiens (Fr.) Kühner.


The generic name Coprinellus indicates that this mushrooms genus is (or was thought to be) closely related to or at least similar to fungi in the genus Coprinus, which literally means 'living on dung' - that's true of quite a few of the inkcaps but not particularly apt for this and several other Coprinellus species. The suffix -ellus indicates fungi that produce rather smaller fruitbodies than those of Coprinus species. The specific epithet impatiens comes directly from the Latin word for 'impatient' or 'intolerant' and may refer to the texture of these fungi which crumble easily if touched.

Common names change with time and location. In America the terms Inky Cap or Inky-cap are most commonly used, while in many older field guides published in Britain you are likely to see Ink Cap or Ink-cap rather than Inkcap.

Identification guide


2 to 4cm across, initially oval becoming convex and finally bell-shaped; deeply furrowed; light ochre with a light orange central ’eye’; turning grey and eventually black but not deliquescing.


Adnexed or free; creamy-beige, turning grey.


4 to 9cm long and 0.2 to 0.4cm dia.; white; silky smooth; no ring.



Ellipsoidal, smooth, 9-12 x 5-6µm; with a central germ pore. The spores are noticeably larger than those of Coprinellus disseminatus (7-9.5 x 4-5µm) and Coprinellus micaceus (7-10 x 4.5-6µm) with which Coprinellus impatiens is sometimes confused.

Spore print

Very dark brown, almost black.


Not distinctive.

Habitat & Ecological role

Saprobic, appearing singly or more often in small groups among leaf litter beneath deciduous broadleaf trees, notably Beeches, and nearly always on lime-rich soil..


June to November.

Similar species

The Glistening Inkcap, Coprinellus micaceus, is of similar size and colouring but when young the caps are covered in mica-like scales; its spores are significantly smaller than those of Coprinellus impatiens.

Culinary Notes

Coprinellus impatiens is variously reported to be either inedible, of doubtful edibility or 'suspect'. It is not one for the pot!

Reference Sources

Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Orton, P.D. & Watling, R. (1979). British Fungus Flora: Agarics and Boleti. Vol 2. Coprinaceae: Coprinus. Royal Botanic Garden: Edinburgh.

Redhead SA, Vilgalys R, Moncalvo J-M, Johnson J, Hopple JS Jr.; Vilgalys, Rytas; Moncalvo, Jean-Marc; Johnson, Jacqui; Hopple, Jr. John S (2001). 'Coprinus Pers. and the disposition of Coprinus species sensu lato.'. Taxon (International Association for Plant Taxonomy (IAPT)) 50 (1): 203–41.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi.

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