Meottomyces dissimulans (Berk. & Broome) Vizzini

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

Meottomyces dissimulans, southern England

Meottomyces dissimulans, an apparently uncommon mushroom occurring in litter beneath deciduous trees and bushes in woodland habitats.

Although there are relatively few formal records of the close relative of the scalycaps (Pholiota species), this is probably because it fruits very late in the season (often around the turn of the year) when few other fungi can be found - hence it is a time when people interested in finding and identifying fungi rarely venture into woodlands.

Stem and gills closeup, Meottomyces dissimulans

The stem ring is clearly visible on the pristine fruitbodies seen above, but the rings a fleeting and rarely evident on older specimens.

Distribution

Probably not such an uncommon species, but found rarely in Scotland and only occasionally in England - nearly always in the south and midlands - and not yet (as I write in January 2014) formally recored from Wales or Ireland, Meottomyces dissimulans is recorded in most parts of mainland Europe from Sweden right down to Portugal. There are reports of this species being found also in North America, but it is possible that these records are erroneous and the result of confusion with the very similar American species Meottomyces mutans, which has a more substantial membranous stem ring.

Taxonomic history

This late-fruiting mushroom was described in 1882 by British mycologists Miles Joseph Berkeley and Christopher Edmund Broome (1812 - 1866), who gave it the scientific name Agaricus dissimulans. The currently-accepted scientific name Meottomyces dissimulans dates from a 2008 publication by the Italian mycologist Alfredo Vizzini, who established the new genus Meottomyces in which this is currently the only known British species.

Synonyms of Meottomyces dissimulans include Agaricus dissimulans Berk. & Broome, Agaricus oedipus Cooke, Hypholoma oedipus (Cooke) Sacc., Pholiota dissimulans (Berk. & Broome) Sacc.Psathyrella oedipus (Cooke) Konrad & Maubl., Dryophila sordida Kühner, Pholiota oedipus (Cooke) P. D. Orton, Phaeogalera oedipus (Cooke) Romagn., Hemipholiota oedipus (Cooke) Bon, and Phaeogalera dissimulans (Berk. & Broome) Holec.

Meottomyces dissimulans, England

Etymology

The Meotto- prefix to the generic name Meottomyces may be honouring the Italian mycologist (a leading Truffle expert) Francesco Meotto; and the suffix -myces means fungus. The specific epithet dissimulans means 'one who is in disguise'.

Identification guide

Cap of Meottomyces dissimulans

Cap

1 to 4cm in diameter, initially convex but eventually flattening; surface greasy to somewhat viscid, hygrophanous mainly in a region near to the margin, colours rather variable but generally brown when young, sometimes tinged with olive, and with a darker middle, becoming greyer when old. Pale veil fragments often cling to the cap margin of young specimens.

Gills and stem of Meottomyces dissimulans

Gills

The broadly adnate gills are pale grey becoming greyish brown, darkening with age; they have finely serrate edges.

Stem

5 to 8mm in diameter and 3 to 6cm tall; pallid reddish-brown to grey-russet and soft with longitudinal fibres and a fleeting membranous ring.

Spores, Meottomyces dissimulans

Spores

Ellipsoidal to ovoid, smooth, 6.5-8 x 4-6μm; with oil drops. (The basdia are nearly all four spored sometimes with just the occasional two-spored basidium.)

Show larger image

Spore print

Dark brown.

Odour/taste

Not distinctive

Habitat & Ecological role

On leaf and twig litter beneath deciduous trees, particularly ash, poplar, hawthorn, sycamore and elm.

Season

Winter (mainly November to January in Britain and Ireland).

Similar species

Kuehneromyces mutabilis is also usually two-toned; its gills are ochraceous when young, becoming cinnamon at maturity.

Culinary Notes

Despite their attractive appearance, these are not edible mushrooms.

Meottomyces dissimulans, Somerset, UK

Reference Sources

Nick Legon, Fungal Portraits No. 49: Meottomyces dissimulans; Field Mycology Volume 13, Issue 1, January 2012, Pages 3–7; British Mycological Society.

Holec, J. (2003). Taxonomy and nomenclature of Pholiota dissimulans with respect to Phaeogalera oedipus. Sydowia 55: 79-85.

Vizzini, A. (2008). Novitates Miscellanea in Rivista di Micologia 51: 63-66.

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.

Meottomyces dissimulans group, Cambridgeshire

Acknowledgements

Pictures on this page were kindly contributed by Simon Harding and Richard Shotbolt.

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