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Leratiomyces squamosus (Pers.) Bridge & Spooner - Slender Roundhead

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

Leratiomyces squamosus - Slender Roundhead, Northwest France

Seen from the top, this attractive little mushroom could easily be mistaken for Sulphur Tuft Hypholoma fasciculare, but it has a substantial and persistent stem ring.

Distribution

The Slender Roundhead Leratiomyces squamosus var. squamosus is an occasional find in England, Scotland, Ireland and Wales (where it is recorded very occasonally in the east). Leratiomyces squamosus var. thraustus is a much rarer find in Britain and Ireland, where it does not have a generally-accepted English name. The autonomous variety is quite a common find in deciduous and mixed woodlands in Germany, Poland, France and several other countries in central mainland Europe; it is also an occasional find in Scandinavia and in som eMediterranean countries as well as North Africa. Leratiomyces squamosus var. thraustus seems to be the more common variety in North America, where both variety are known to occur.

In warm coastal areas of France Leratiomyce squamosus sometimes carpets the forest floor beneath pines and other conifers where there is sawdust and wood chip from thinning and felling. Elsewhere in central and southern mainland Europe this attractive little mushroom is a very common sight on heaps of sawdust on roadside verges where trees have been felled.

Leratiomyces squamosus, Slender Roundhead, Hesdin, France

Taxonomic history

When in 1888 British mycologists Mordecai Cubitt Cooke and George Edward Massee (1850 - 1917) described this species, they gave it the binomial scientific name Agaricus squamosus. (In the early days of fungal taxonomy most gilled fungi were initially placed in the genus Agaricus, the contents of which has since redistributed across many other newer genera.)

In 2008 Brian Spooner and colleagues established the currently-accepted scientific name of this mushroom as Leratiomyces squamosus.

Synonyms of Leratiomyces squamosus include

Agaricus squamosus Pers., Syn. meth. fung. (Göttingen) 2: 409 (1801) Psalliota squamosa (Pers.) P. Kumm., Führ. Pilzk. (Zerbst): 73 (1871) Stropharia squamosa (Pers.) Quél., Mém. Soc. Émul. Montbéliard, Sér. 2 5: 348 (1873) Stropharia squamosa (Pers.) Quél., Mém. Soc. Émul. Montbéliard, Sér. 2 5: 348 (1873) var. squamosa Geophila squamosa (Pers.) Quél., Enchir. fung. (Paris): 111 (1886) Naematoloma squamosum (Pers.) Singer, Sydowia 2(1-6): 36 (1948) var. squamosum Naematoloma squamosum (Pers.) Singer, Sydowia 2(1-6): 36 (1948) Psilocybe squamosa (Pers.) P.D. Orton, Notes R. bot. Gdn Edinb. 29(1): 80 (1969) Psilocybe squamosa (Pers.) P.D. Orton, Notes R. bot. Gdn Edinb. 29(1): 80 (1969) var. squamosa Hypholoma squamosum (Pers.) Urbonas [as 'squamosa'], Liet. TSR Mokslu Akad. Darb., Ser. C 4(no. 72): 12 (1975) Hypholoma squamosum (Pers.) Urbonas, Liet. TSR Mokslu Akad. Darb., Ser. C 4(no. 72): 12 (1975) var. squamosum Stropholoma squamosum (Pers.) Balletto [as 'squamosus'], Micol. Ital. 18(1): 36 (1989) Stropholoma squamosum (Pers.) Balletto, Micol. Ital. 18(1): 36 (1989) var. squamosum Hypholoma squamosum (Pers.) Urbonas [as 'squamosa'], Lietuvos Grybai (Vilnius) 8(3): 128 (1999) Stropholoma squamosum (Pers.) Ryman [as 'squamosa'], Funga Nordica, Agaricoid, Boletoid and Cyphelloid Genera (Gylling): 913 (2008)

Etymology

This genus name originated in 1907 when Narcisse Théophile Patouillard created the name Le Ratia (which he applied to a puffball fungus) in honour of French botanist and plant collector Auguste-Joseph Le Rat (1872 - 1910), who on various occasions had provided Patouillard with fungal specimens that he had collected. From this origin Spooner and colleagues derived the new genus name Leratiomyces.

The specific epithet squamosus is a reference to the (usually!) cherry red colour of caps of the Redlead Roundhead.

Toxicity

Despite an attractive appearance, this inedible species is likely to cause an upset stomach if it is eaten. (The very similar Leratiomyces squamosus is known to contain hallucinogenic psilocybin/psilocin.)

Identification guide

Cap of Leratiomyces squamosus, the Slender Roundhead

Cap

Yellowish ochre to pale orange; convex, becoming flatter when old; pale veil fragments usually cling to cap, especially towards the margin; 2 to 6cm across.

Gills of Leratiomyces squamosus, the Slender Roundhead

Gills

Adnate; fairly crowded; initially grey-brown becoming mottled purplish-brown with paler edges.

Stem

6 to 11cm tall and 4 to 9mm diameter, hollow; white at apex, flushed brownish towards base; covered in fibrous white scales below a persistent stem ring.

Spores of Leratiomyces squamosus

Spores

Ellipsoidal, smooth, 11-14 x 6.-8.5; with a germ pore.

Show larger image

Spore print

Purple-brown.

Odour/taste

Not distinctive.

Habitat & Ecological role

Most often found in alkaline-soil areas on hardwood mulch or in deciduous woodlands where twigs and leaves accumulate in damp grassy or mossy areas.

Season

July to November in Britain and Ireland.

Similar species

Sulphur Tuft Hypholoma fasciculare often has veil fragments near the cap rim, but they are darker; it also lacks a stem ring.

Reference Sources

J. Breitenbach, F. Kränzlin: Mushrooms of Switzerland, Volume 4. Publisher Mykologia, Lucerne 1995, ISBN 3-85604-040-4

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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