Tricholomopsis decora (Fr.) Singer - Prunes and Custard

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

Tricholomopsis decora - Prunes and Custard at RSPB Sandy, Bedfordshire

Quite a rare find in southern Britain and Ireland, although more common in Scotland, this beautiful but inedible mushroom grows on conifer stumps, fallen trunks and branches and (as in the picture below, taken at RSPB headquarters at Sandy, in Bedfordshire, England) untreated pine fence posts that are well past their sell-by date.

Closely related to Tricholomopsis rutilans, or Prunes and Custard, this unusual find is in a less flamboyant way just as beautiful.

Tricholomopsis decora on a pine stump, Scotland

Distribution

This beautiful mushroom is a very rare find in most of Britain and Ireland, although it is recorded more frequently in parts of Scotland and is also found in many northern countries of mainland Europe.

Tricholomopsis decora, southern England

Taxonomic history

Originally described in 1821 by the great Swedish mycologist Elias Magnus Fries, who named it Agaricus decorus - most gilled fungi were initially placed in a giant Agaricus genus, now redistributed to many other genera - Prunes and Custard acquired its currently accepted scientific name Tricholomopsis decora in 1939, when the German-born mycologist Rolf Singer transferred it to the new genus (which was defined by Singer himself) of Tricholomopsis.

Synonyms of Tricholomopsis decora include Agaricus decorus Fr., Clitocybe decora (Fr.) Gillet, Tricholoma decorum (Fr.) Quél., and Pleurotus decorus (Fr.) Sacc.

Tricholomopsis decora, view of gills and stem

Etymology

The genus Tricholomopsis, established by Rolf Singer in 1939, lies somewhere between the genera Clitocybe (many of the fungi within which were formerly - Classed as Tricholoma species) and Tricholoma, and the term Tricholomopsis means 'similar to a Tricholoma'. (Tricho- as a prefix refers to hair.) The specific epithet decora means

Identification guide

Immature and mature caps of Tricholomopsis decora

Cap

Golden yellow, covered with fine grey-brown scales concentrated towards the centre of the cap; convex, becoming broadly umbonate or almost flat at maturity, often with a shallow central depression; margin slightly wavy when fully expanded; 4 to 10cm dia.

Gills of Tricholomopsis decora

Gills

Pale yellow to deep yellow; sinuate; crowded.

Cross-section of stem, Tricholomopsis decora

Stem

Pale yellow background covered in fine brown scales; 5 to 10cm tall and 0.6 to 1.6cm in diameter; no stem ring.

Spore, Tricholomopsis decora

Spores

Ellipsoidal, smooth, 6-8 x 4-5µm; inamyloid.

Show larger image

Spore print

White.

Odour/taste

Not distinctive. 

Habitat & Ecological role

Saprobic, on pine stumps and fallen branches.

Season

June to October in Britain and Ireland.

Similar species

The close relative Tricholomopsis rutilans, commonly known as Plums and Custard, has a wine-red cap and wine-red stem scales on a yellow background; it is much more common than Prunes and Custard and occurs on most kinds of rotting conifer timber.

Culinary Notes

Despite its tempting common name and attractive appearance, Tricholomopsis decora is just as bitter and inedible as its better known relative Tricholoma rutilans, Plums and Custard.

Tricholomopsis decora, Hampshire, southern England

Acknowledgements

This page includes pictures kindly contributed by David KellyDavid Kelly

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

Funga Nordica: 2nd edition 2012. Edited by Knudsen, H. & Vesterholt, J. ISBN 9788798396130

Grid maps of records, NBN Gateway

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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