Trees Birds Mammals Fish Amphibians Reptiles
Wild Algarve
Bookshop
Tricholoma atrosquamosum var. squarrulosum (Bres.) Mort. Chr. & Noordel. - Dark Scaled Knight
Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Tricholomataceae
Distribution - Taxonomic History - Etymology - Identification - Culinary Notes - Reference Sources

A rare find in Britain and Ireland, Tricholoma atrosquamosum var. squarrulosum is a mycorrhizal mushroom of mainly deciduous woodland in areas of alkaline soil. Some authorities treat this mainly southern-Europe mushroom as a separate species Tricholoma squarrulosum (by which name it is generally referred to in the USA) because the autonomous variety found in Scandinavia and other parts of northern Europe (and probably not authentically recorded from Britain or Ireland) Tricholoma atrosquamosum var. atrosquamosum has significantly smaller spores and a stem with very few black scales.
Knights (Tricholoma species) are sometimes difficult to identify with absolute certainty, and unless studied very carefully less scaly specimens of Tricholoma atrosquamosum could easily be confused with other dark-grey knights such as Tricholoma terreum.
Distribution
Being a mycorrhizal mushroom, the fruitbodies recur in the same location year after year; however, in Britain relatively few such locations are known, mainly in southern parts of England and Wales. This beautiful mushroom occurs also in many parts of central and southern mainland Europe and in some parts of North America.
Taxonomic history
The basionym of this species dates from 1877, when Italian mycologist Pier Andrea Saccardo described this species and gave it the binomial nameTricholoma atrosquamosum., which remains its generally-accepted scientific name.
Synonyms of Tricholoma atrosquamosum include Agaricus atrosquamosus Chevall., Tricholoma terreum var. atrosquamosum (Sacc.) Massee, and Tricholoma nigromarginatum Bres.
Tricholoma atrosquamosum var. squarrulosum (Bres.) Mort. Chr. & Noordel., was first described in 1892 by Italian mycologist Giacopo Bresadola (1847-1929) and given the name Tricholoma squarrulosum. The generally-accepted (in Britain and Europe) name Tricholoma atrosquamosum var. squarrulosum dates from a 1999 publication in Persoonia by Danish mycologist Morten Christensen and Dutch mycologist Machiel Noordeloos (b. 1946).
Etymology
Tricholoma was established as a genus by the great Swedish mycologist Elias Magnus Fries. The generic name comes from Greek words meaning 'hairy fringe', and it must be one of the least appropriate mycological genus names, because very few species within this genus have hairy or even shaggily scaly cap margins that would justify the descriptive term.
The specific epithet atrosquamosum comes from Latin and means 'having black scales'; it refers to the blackish scales that cover the caps of these mushrooms.
Identification guide
 |
Cap
Dark grey (sometimes almost black) and covered with recurved pointed scales; initially woolly and paler at the margin, the caps are convex at first, becoming broadly umbonate and expanding to between 4 and 10cm in diameter.
The flesh of the cap and of the stem is greyish and does not change colour significantly on exposure to air. |

|
Gills
Light grey at first, often developing black-spotted margins as they age, the gills are sinuate (notched near the stem).
Stem
Grey, covered with dense black scales; 4 to 8cm long, 1 to 1.8cm diameter; no stem ring. |
 |
Spores
Ellipsoidal, smooth, 6-8 x 3.5-6μm; inamyloid.
Spore print
White. |
Odour/taste |
Odour faintly mealy; taste mealy or slightly peppery. |
Habitat & Ecological role |
Ectomycorrhizal with deciduous broadleaf trees - mainly beech in Britain. |
Season |
Late summer and autumn in Britain; sometimes right through to December in parts of southern Europe. |
Similar species |
Tricholoma terreum and several other of the greyish knights could be mistaken for the Dark Scaled Knight is not examined very carefully. |
Culinary Notes
Although reported to be edible and of moderate quality, Tricholoma atrosquamosum var. squarrulosum is very rare in Britain. We therefore do not consider that this species should be treated as a culinary collectible.
Reference Sources
Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.
Kibby, G (2013) The Genus Tricholoma in Britain, published by Geoffrey Kibby
Funga Nordica: 2nd edition 2012. Edited by Knudsen, H. & Vesterholt, J. ISBN 9788798396130
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.
Top of page...
Fascinated by Fungi. Back by popular demand, Pat O'Reilly's best-selling 450-page hardback book is available now. The latest second edition was republished with a sparkling new cover design in September 2022 by Coch-y-Bonddu Books. Full details and copies are available from the publisher's online bookshop...