Coprinellus xanthothrix (Romagn.) Vilgalys, Hopple & Jacq. Johnson

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

Coprinellus xanthothrix in dune grassland

This rather uncommon wood-rotting inkcap looks very much like a pale grey form of the Glistening Inkcap (also known as the Mica Inkcap), Coprinellus micaceus, and indeed confident separation of the two species really requires microscopic analysis: Coprinellus xanthothrix, which has no generally accepted common name, has oval spores (in contrast with the spores of Coprinellus micaceus, which are mitre shaped) and the cystidia on the edges of its gills are flask shaped.

Distribution

Uncommon in Britain and Ireland, Coprinellus xanthothrix is found throughout mainland Europe.

Coprinellus xanthothrix

Taxonomic history

This inkcap mushroom was described scientifically in 1941 by French mycologist Henri Charles Louis Romagnesi (1912 - 1999), who named it Coprinus xanthothrix. It was known by that name 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 this inkcap being moved into the genus Coprinellus.

Synonyms of Coprinellus xanthothrix include Coprinus xanthothrix Romagn.

Etymology

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 xanthothrix is obscure but may stem from xanthos, a Greek word meaning yellow.

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

Cap of Coprinellus xanthothrix

Cap

Initially egg-shaped then bell shaped, expanding to between 1.6 and 2.5cm dia; margin deeply furrowed; surface sparsely covered with pale mica-like scales, mainly near to the centre of the cap; pale buff becoming greyer at maturity.

Gills of Coprinellus xanthothrix

Gills

The adnate gills are white at first, turning grey and then blackening.

Stem

The hollow white stem is typically 2.5 to 5mm in diameter, slightly swollen near the base, and up to 10cm tall. 

 

Spores

Ellipsoidal to ovoid, smooth, 7.5-10 x 5-6µm, with a germ pore.

Spore print

Black.

Odour/taste

Not distinctive.

Habitat & Ecological role

Saprobic, on or beside broad-leaved tree stumps and dead roots.

Season

May to November in Britain.

Similar species

Coprinellus micaceus is similar but is brown rather than grey at maturity; its spores are mitre shaped rather than oval.

Coprinellus disseminatus also appears in large groups but is smaller and does not have mica-like granules on its cap surface.

Culinary Notes

Coprinellus xanthothrix is not known to be edible.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

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.

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