Chlorophyllum rhacodes (Vittad.) Vellinga - Shaggy Parasol

Distribution - Taxonomic History - Etymology - Toxicity -Identification - Reference Sources

Chlorophyllum rhacodes - Shaggy Parasol, on a woodland edge

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

Family: Agaricaceae

Chlorophyllum (formerly Macrolepiota) rhacodes, the Shaggy Parasol, is a fairly common mushroom found mainly in or beside woods and hedges. It is smaller than the Parasol Mushroom, Macrolepiota  procera, and its stem lacks the snakeskin-like patterning associated with the Parasol. (See the Identification Guide, below.)

Distribution

Frequent in Britain and Ireland, Shaggy Parasols occur throughout Europe and North America.

Chlorophyllum rhacodes - Shaggy Parasol, woodland setting

If you find fungi that look rather like Shaggy Parasols in open grassland, don't be too hasty in labelling them as such; there are several other large parasol-like fungi that appear occasionally in meadows, in dune grassland and in parkland.

See also Agaricus augustus, commonly known as The Prince, as this large mushroom could also be mistaken for a Shaggy Parasol unless you look carefully at all of its identifying features.

Taking a spore print (for which a mature fruitbody is necessary) would quickly resolve any such uncertainty, as the Shaggy Parasol produces very pale cream spores while Agaricus species produce dark brown or purplish-brown spores.

The splendid specimens shown on the left were photographed by Doug Holland, to whom we are grateful for permission to show this picture.

 - Walker

Taxonomic history

The taxonomy of this species has changed recently. Originally described in 1835 by Italian medic and mycologist Carlo Vittadini (1800-1865), who erroneously transcribed the Greek word rhakos, meaning 'a piece of cloth' (this mushroom does often look rather ragged!), to the Latinised form rachos, resulting in the specific epitet rachodes rather than rhacodes. Some older reference texts that you may come across may therefore use the scientific name Macrolepiota rachodes for this species. (Another deprecated synonym for this species is Lepiota rhacodes.)

As a result of molecular studies (DNA analysis), in 2003 the genus Macrolepiota was split up and the Shaggy Parasol was transferred to the genus Chlorophyllum, where it resides with other poisonous parasol-like mushrooms. (Macrolepiota procera, the popular edible Parasol, stayed put!)

The lovely specimen on the left demonstrates that the Shaggy Parasol can occasionally be an exquisitely beautiful mushroom.

Picture above © Walker - The Walker Touch

Taxonomic history

Described under the name Agaricus rhacodes by Carlo Vittadini (1800 - 1865) in 1835, this large and stocky mushroom has since spent time in the general Lepiota and Macrolepiota until, in 2002, DNA study by Else C Vellinga of the University of California justified its transportation to the genus Chlorophyllum. Common synonyms of Chlorophyllum rhacodes include Agaricus rhacodes Vittad., Lepiota rhacodes (Vittad.) Quél., Lepiota procera var. rhacodes (Vittad.) Massee, Macrolepiota rhacodes (Vittad.) Singer, and Macrolepiota venenata Bon.

Etymology

Chlorophyllum rhacodes - Shaggy Parasol, closeup of ring structure

The generic name Chlorophyllum means 'with green gills' and is a reference to the green-gilled poisonous mushroom Chlorophyllum molybdites, which is common in North America. Other species in this genus have white spores, as indeed does Chlorophyllum rhacodes. The origin of the specific epithet rhacodes is unclear, as it was spelt either rachodes, rhachodes or rhacodes in early mycological publications. The basis may be Greek words meaning either 'rag' (as in raggy scales, which seems most likely) or less plausibly 'bush' (a reference to the habitat needs of this mushroom, possibly).

Toxicity

Many books and websites state that this is a good edible mushroom, but the Shaggy Parasol has been known to cause serious illness in some people and so picking it to eat, intentionally or otherwise, should be avoided.

Identification guide

Cap of Chlorophyllum rhacodes - Shaggy Parasol

Cap

Initially bun shaped, the cap of Chlorophyllum rhacodes expands and becomes convex. Only rarely do Shaggy Parasols open out completely flat. (Picture: Doug Holland)

At maturity, the cap diameter ranges from 5 to 15cm; its flesh reddens when cut.

Gills of Chlorophyllum rhacodes - Shaggy Parasol

Gills

The gills are soft, white, free and crowded. If the gills are bruised or cut, they turn reddish - as also does the cap flesh if it is cut.

Stem and ring of Chlorophyllum rhacodes - Shaggy Parasol

Stem

The stem of a Shaggy Parasol is white, tinged with red-brown, and it rises eccentrically from a large bulbous base. The stem diameter is between 1.8 and 2.4cm, and the stem flesh turns reddish when cut or bruised.

A movable white double ring, the same colour as the stem, sometimes falls to the base as the fruitbody matures.

Spores of Chlorophyllum rhacodes, Shaggy Parasol

Spores

Broadly ellipsoidal to globose or pyriform (pear-shaped), smooth, 8.8-12.7 x 5.4-7.9 µm, with a germ pore; hyaline; dextrinoid.

Spore print

White or pale cream.

Odour/taste

Taste not distinctive; odour quite pleasant.

Habitat

Chlorophyllum rhacodes is saprobic and occurs in all kinds of woodland and sometimes in humous-rich disturbed soil in gardens.

Season

June to October in Britain and Ireland.

Similar species

Macrolepiota procera, the Parasol, has smaller scales and a brown and white pattern, often like snakeskin, on the stem.

Chlorophyllum rhacodes, France, October 2012

Reference Sources

Fascinated by Fungi, Pat O'Reilly, Published by First Nature, 2011.

Elsa C Vellinga, de Kok RPJ, Bruns TD. (2003). Phylogeny and taxonomy of Macrolepiota (Agaricaceae). Mycologia 95 (3): pp 442–56.

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.

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.