Coprinopsis picacea (Bull.) Redhead, Vilgalys & Moncalvo - Magpie Inkcap

Distribution - Taxonomic History - Etymology - Identification - Toxicity - Reference Sources

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

It is always a delight to come across a Magpie Inkcap. So often are they solitary or so spaced that those of us who like to photograph our finds have little prospect of capturing a photogenic group (a ‘parliament’ of magpies) that we can crow about to others!

The wonderful patterning of white or silvery grey on a shiny dark-brown background makes this one of the most beautiful mushrooms to photograph for reproduction as a monochrome print. Like all inkcaps the fruitbodies are short lived, and so a patient observer could have an educational day watching a cap expand from an elongated egg to conical and then bell-like as the cottony universal veil remnant breaks into separate patches to reveal the glossy dark background. As with other large inkcaps, the gills of the Magpie Inkcap deliquesce, a process which aids spore dispersal particularly in wet weather.

Distribution

Infrequent in Britain and Ireland, the Magpie Inkcap is found throughout Europe but most commonly in areas with alkaline soil. This attractive species occurs also in parts of North America.

Coprinopsis picacea, Magpie Inkcap, in a grassland setting

Taxonomic history

The Magpie Inkcap was first described scientifically in 1785 by Jean Baptiste Francois Pierre Bulliard, who gave it the scientific name Agaricus picaceus. (Vast numbers of gilled fungi were dumped into the Agaricus genus in the early days of fungal taxonomy; most have since been moved to other genera leaving in the present-day Agaricus genus a much smaller number of gilled mushrooms that are sometimes referred to as the 'true mushrooms'.)

The Magpie Inkcap was known by the name that Bulliard gave it until 2001 when, as a result of molecular (DNA) analysis, by Redhead, Vilgalys & Moncalvo the large 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 Magpie Inkcap being moved into the genus Coprinopsis within the family Psathyrellaceae. Coprinus comatus, the Shaggy Inkcap (with which the Magpie Inkcap is sometimes confused) plus three other rare fungi are all that now remains of the formerly large Coprinus genus; however, many field guides and websites are yet to be updated in this respect.

Etymology

The generic name Coprinopsis indicates that this mushrooms genus is similar to 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 species. The specific epithet picacea comes from the Latin scientific name for the Eurasian Magpie, Pica pica.

Toxicity

Unlike the Shaggy Inkcap, the Magpie Inkcap is reported to be poisonous - perhaps further evidence of the genetic distance between them. In any case these are quite rare finds in most areas and best left for others to see and enjoy.

The specimens shown above were found and photographed in the Algarve region of southern Portugal; their cap backgrounds are very dark brown (almost black) and fully justify the common name reference to a magpie, which in Britain and Ireland at least is a black-and white bird. (Enigmatically, magpies with blue backs - Azure-backed Magpies - are far more common in southern Portugal.)

In some locations the Magpie Inkcap more often has a mid brown background, as in the examples on the left, photographed in the USA by Doug Holland, with whose kind permission they are shown here.

Note: inkcap is sometimes written as ink-cap or ink cap, and in the USA the terms inky cap or inky-cap are used.

Identification guide

	Cap At maturity the caps of Coprinopsis picacea are 3 to 7cm across and 7 to 12cm tall; initially egg-shaped, becoming bell shaped, the margins turning outwards before blackening and deliquescing from the rim; very dark grey-brown glossy background covered with silvery-white fibrils that separate into patches as the cap expands. The young cap shown here has not yet expanded fully, and at this stage it could be mistaken for a Shaggy Inkcap, Coprinus comatus.
Gills	Adnate or free, the gills of the Magpie Inkcap are crowded, white, turning reddish and then black before deliquescing.
	Stem 10 to 20cm long and 0.7 to 1.5cm diameter, the surface of the stem of the Magpie Inkcap, Coprinopsis picacea, is white and floccose; its stem base is often slightly bulbous.
	Spores Ellipsoidal, smooth, 13-19 x 10-13µm; with a central germ pore. Spore print Black.
Odour/taste	Not distinctive.
Habitat	Generally as solitary specimens or well spaced in small groups, Magpie Inkcaps occur most often in deciduous woodland, particularly under Beech trees and less frequently under oaks. They are rare finds in Britain and Ireland, where they are mainly restricted to alkaline areas. Occasionally I find them also in damp, well-shaded grassland where deciduous hardwood debris has collected at the edge of a floodplain.
Season	May to November in Britain and Ireland; later in southern Europe.
Similar species	It would be difficult to mistake this lovely inkcap for any other species once its cap has begun expanding to reveal the glossy brown background underlying the white patches.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2011.

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 and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.