Clitopilus prunulus (Scop.) P. Kumm. - The Miller

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

Clitopilus prunulus - The Miller

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

Family: Entolomataceae

With its smooth matt cap surface and mealy smell it ought to be difficult to confuse this common mushroom of forest tracksides and woodland-edges with any of the white or grey-capped poisonous species, but it does happen and sometimes with serious consequences, because it has toxic lookalikes.

The deeply decurrent gills are a helpful diagnostic feature, clearly differentiating The Miller from most poisonous white-capped fungi.

Distribution

Widespread and fairly common in Britain and Ireland as well as in most countries of mainland Europe and parts of Asia, Clitopilus prunulus is also reported from North America.

Taxonomic history

The Miller was first described scientifically in 1772 by Joannes Antonius Scopoli (1723 - 1788), who named it Agaricus prunulus. (Most gilled fungi were initially placed in a giant Agaricus genus, now redistributed to many other genera.) German mycologist Paul Kummer transferred this species to the new (then) genus Clitopilus in 1871, and it retrains that name today.

Clitopilus prunulus has many synonyms including Agaricus prunulus Scop., Agaricus orcellus Bull., Clitopilus orcellus (Bull.) P. Kumm., and Paxillopsis prunulus (Scop.) J. E. Lange.

Etymology

The specific epithet prunulus is nothing to do with prunes; it means pruinose - frosted or covered in a fine white powder, which is a characteristic of caps of this mushroom.

Identification guide

Caps of Clitocybe prunulus

Cap

White or pale grey with cream or pink tints; matt or finely frosted like fine suede or chamois leather; 5 to 12cm across; irregularly convex and developing a central depression; margin undulating and sometimes lobed; retaining an incurved margin; flesh firm and white.

Gills and stem of Clitocybe prunulus

Gills

White at first, becoming pink; deeply decurrent; many of the gills forking.

Stem

White or grey often with a cream or pink tinge; 2 to 4cm wide and solid; more or less cylindrical, the stem of Clitopilus prunulus is 1.5 to 4cm tall (relatively short for such a large mushroom) and often the attachment is slightly eccentric. There is no stem ring.

Spores of Clitopilus prunulus

Spores

Ellipsoidal, oblong or amygdaloid; 9-12 x 4-6μm; ornamented with 6 to 8 longitudinal ridges.

Spore print

Pink.

Basidium of Clitopilus prunulus

Other microscopic characters

The basidia are four-spored - see picture on the left.

Odour/taste

The Miller gets its common name from its mealy odour and taste.

Habitat

Look for Clitopilus prunulus in grassy clearings in deciduous woods; beneath hedges on roadside verges; occasionally under broadleaf trees in parkland.

Season

June to late November in Britain and Ireland.

Similar species

This mushroom could be confused with St George's Mushroom, Calocybe gambosa, which usually fruits from Springtime until early summer.

Many other white-capped fungi in the family Tricholomataceae occur in similar habitats - Clitocybe nebularis, is one such example - but gill colour and odour help differentiate The Miller from the many other pale funnel-shapede fungi.

Culinary Notes

Although edible, The Miller is not among the most highly rated of mushrooms, and so for safety reasons is probably best avoided except by very experienced fungi foragers.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2011

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.