Gymnopilus dilepis  (Berk. & Broome) Singer - Magenta Rustgill

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

Gymnopilus dilepis, Magenta Rustgill

Growing on stumps or on dead conifer wood, most particularly of pine trees, buried in the litter of the forest floor, this beautiful mushroom is not easily confused with most other members of its genus because nearly all of them have orange caps.

Distribution

The Magenta Rustgill is a rare find in Britain, where formal records are concentrated in southern England, mainly in the south east, but it is also known to occur in East Anglia.

Gymnopilus dilepis, Magenta Rustgill, North America

The Magenta Rustgill is much more common in southern Europe, and it is also recorded in many parts of North America as well as India and Australia. This mushroom is native to Southeast Asia, from where it has spread to many other parts of the world.

Taxonomic history

This mushroom was described in 1871 by British mycologists Miles Joseph Berkeley and Christopher Edmund Broome (1812 - 1866), when the Magenta Rustgill was given the scientific name Agaricus dilepis. It was German-American mycologist Rolf Singer who, in a 1951 publication, transferred this species to its present genus and thereby established its currently-accepted scientific name Gymnopilus dilepis.

Above: Magenta Rustgills on chipped wood, Picture cortesy of Doug Holland, USA.

Synonyms of Gymnopilus dilepis include Agaricus dilepis Berk. & Broome, Flammula dilepis (Berk. & Broome) Sacc., and Naucoria dilepis (Berk. & Broome) Cout.

Etymology

Gymnopilus was proposed as a new genus name in 1879 by the Finnish mycologist Petter Adolf Karsten (1834 - 1917). The origin of this generic name is the prefix Gymn- meaning naked, and the suffix -pilus which means cap - hence naked or bald caps would normally be an expected feature of the mushrooms in this genus.

The specific epithet dilepis means 'with two scales' or perhaps 'with scales in pairs'. The origin is unclear to me except, of course, that this is indeed a scaly-capped mushroom.

Toxicity

The Magenta Rustgill is inedible and may even be poisonous; certainly some Gymnopilus fungi have been found to contain seriously poisonous chemicals.

Identification guide

Young cap of Gymnopilus dilepis, Magenta Rustgill

Cap

4 to 8cm across; becoming almost flat but usually retaining a broad central umbo; felted when young, usually (but not always) breaking up into scales and sometimes cracking; purple becoming more orange-brown when old.

Gills of Gymnopilus dilepis

Gills

Adnate; crowded; yellow, turning yellowish-brown when the spores mature.

Stem

4 to 8cm long and 1 to 2cm in dia., more or less cylindrical; smooth, with fine longitudinal fibres; yellowish flushed with cap colour; a fragile, sometimes ephemeral stem ring that becomes stained with spores at maturity.

 

Spores

Ellipsoidal, warty, 6.5-8 x 4.5-5µm.

Spore print

Yellowish brown.

Odour/taste

Not distinctive.

Habitat & Ecological role

Saprobic, on stumps, buried fallen branches and chipped wood of coniferous trees, especially pines.

Season

Autumn in Britain; October through to the New Year in Mediterranean countries.

Similar species

Tricholomopsis rutilans is very similar in appearance but has no stem ring; its spores are white.

Reference Sources

Pat O'Reilly (2016). Fascinated by Fungi

Lincoff, G. and D. J. Mitchel. (1977). Toxic and Hallucinogenic Mushroom Poisoning. Van Nostrand Reinhold, New York.

Bresinsky A, Besl H. (1990). A Colour Atlas of Poisonous Fungi. Wolfe Publishing. ISBN 0-7234-1576-5.

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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