Public Description of Coprinopsis atramentaria (Bull.) Redhead, Vilgalys & Moncalvo

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Name: Coprinopsis atramentaria (Bull.) Redhead, Vilgalys & Moncalvo
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Description status: Unreviewed

Taxonomic Classification:

Domain: Eukarya
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Psathyrellaceae

General Description:

The cap of C. atramentaria is 3cm to 6cm in height and has a conical tip (Image 1). The base of the cone can be as wide as 10cm in diameter. Gray to light brown in color. The gills are white but can turn into a black slurry or “ink”. The stem is 8-15cm high and 6-12cm in diameter.
Image 1

Diagnostic Description:

Spores are 6.5-10.5 × 4-6.5 ┬Ám and have an ellipsoidal shape(Image 2). Spore print is black in color. Clamp connections are present.
Image 2


Widely distributed in North America.


Can be found in clusters or solitary often growing on roots or stumps. Grows on decaying organic matter like rotting wood and wet grasslands.

Solitary to clustered, in grass, often near rotting wood; fruiting from fall to spring, although specimens can be collected any month of the year that moisture is available.

Look Alikes:

Coprinoid mushrooms, like C. atramentarius, all have distinct “inky caps” that is a result of gills that turn to a black color and can liquefy.


This mushroom is edible but should not be consumed if alcoholic beverages are consumed up to several days before. The compound corprine, found in C. atramentaria, can cause symptoms of nausea, facial flushing, and tachycardia when consumed with alcohol. Symptoms can arise withing 20 minutes to 2 hours. No fatalities have been recorded from poisoning.



Hall, Ian; et al (August 1, 2003). Edible and Poisonous Mushrooms of the World. Timber Press. ISBN 978-0-88192-586-9. p. 198.

Kuo, M. (2008, February). Coprinopsis atramentaria. Retrieved from the MushroomExpert.Com Web site:

Stephen A. DeVries
University of Wisconsin – La Crosse
Medical Mycology
May 15, 2009

Description author: Steve (Request Authorship Credit)
Description editor: Johannes Harnisch