Pluteus aurantiorugosus (Trog) Sacc. - Flame Shield

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

Distribution - Taxonomic History - Etymology - Identification - Culinary Notes - Reference Sources

Pluteus aurantiorugosus is a wood-rotting fungus that occurs mainly on broadleaf (hardwood) stumps and large logs of buried hardwood timber, mainly of well-rotted elm trees. This attractive mushroom can appear at any time from early summer right through to the end of autumn.

Distribution

In Britain this is an uncommon find and largely restricted to southern England a South Wales; it has also been recorded at least once in Northern Ireland. This wood-rotting mushroom is also found in many parts of mainland Europe.

Taxonomic history

The basionym of this species was established when the Willow Shield was described in 1857 by Swiss mycologist Jakob Gabriel Trog (1781 - 1865), who gave it the name Agaricus aurantiorugosus.

Synonyms of Pluteus aurantiorugosus include Agaricus aurantiorugosus Trog, Pluteus leoninus var. coccineus Massee, Pluteus caloceps G.F. Atk., and Pluteus coccineus (Massee) J.E. Lange.

Etymology

Pluteus, the genus name, comes from Latin and literally means a protective fence or screen - a shield for example!

The specific epithet aurantiorugosus means gold and granular, a reference to the colour and sometimes granular texture of the cap surface.

Identification guide

	Cap Smooth or finely velvety (rugose!) especially towards the centre, flame orange but often more yellow towards the margin, initially convex and usually flattening with a broad umbo, the caps are typically 3 to 7cm in diameter. The cap flesh is white and firm.
	Pileipelis The cap cuticle is a cystoderm with inflated, rounded terminal cells.
	Gills White at first, becoming pale pink, the gills are broad, crowded and free. Cheilocystidia Gill-edge cystidia are not ornamented with horns. Stem Yellowish to pale orange (but paler than the cap) but darker orange towards the base, untapering, 3 to 6mm in diameter and 3 to 8cm long, striate with fine longitudinal fibres. The woolly base is whitish or yellow, and the stem flesh is white or pale yellow and firm.
	Spores Broadly ellipsoidal, smooth, 5.5-7.5 x 4.5-5.5µm, hyaline. Show larger image Spores of Pluteus aurantiorugosus  X  Spore print Pale pink.
Odour/taste	Not distinctive.
Habitat & Ecological role	Saprobic, usually solitary on long-dead stumps, buried rotting fallen branches and other woody debris of broadleaf trees, particularly elm and sometimes ash.
Season	Fruiting from early summer to late autumn, provided the weather is mild. Most often fruiting from mid summer to mid autumn.
Similar species	Pluteus umbrosus has a darker wrinkled cap and is generally a little smaller. Pluteus cervinus has a smooth brown or fawn cap.

Culinary Notes

It is not entirely clear to me whether Pluteus aurantiorugosus contains Psilocybin, a hallucinogenic substance, and so I consider it inadvisable to gather these mushrooms for eating. (In any case their rarity in Britain and Ireland makes collection not just impractical but ecologically quite inappropriate.)

Reference Sources

Alfredo Justo, Andrew M. Minnis, Stefano Ghignone, Nelson Menolli Jr., Marina Capelari, Olivia Rodríguez, Ekaterina Malysheva, Marco Contu, Alfredo Vizzini (2011). 'Species recognition in Pluteus and Volvopluteus (Pluteaceae, Agaricales): morphology, geography and phylogeny'. Mycological Progress 10 (4): 453–479.

Orton, P.D. (1986). British Fungus Flora: Agarics and Boleti. Vol 4. Pluteaceae: Pluteus & Volvariella. Royal Botanic Garden: Edinburgh, Scotland.

Funga Nordica, Henning Knudsen and Jan Vesterholt, 2008.

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.

Acknowledgements

This page includes pictures kindly contributed by Simon Harding and Zoran Bovovic.

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