Lactarius vietus (Fr.) Fr. - Grey Milkcap

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Russulales - Family: Russulaceae

Lactarius vietus - Grey Milkcap

Lactarius vietus, commonly referred to as the Grey Milkcap, grows mainly under birch trees. It is not one of the milkcaps that turn up on most woodland forays, but in areas where it occurs it is usually quite plentiful and easy to find, despite its drab appearance.


Common and widespread in Britain and Ireland, the Grey Milkcap is also found throughout much of mainland Europe in wet mossy woodland.

Lactarius vietus - Grey Milkcap, Wales UK

The range of this milkcap extends into eastern Asia, and a milkcap under the same scientific name is recorded also in parts of North America.

Taxonomic history

The Grey Milkcap was described in 1821 by the great Swedish mycologist Elias Magnus Fries, who gave it the binomial scientific name Agaricus vietus . (Most of the gilled mushrooms were included placed in the genus Agaricus, but the great majority of them have since been redistributed across several newer genera leaving just the 'true mushrooms' in a slimmed-down Agaricus genus.)

It was also Fries who, in 1838, transferred this woodland mushroom species to its present genus, thereby establishing its name as Lactarius vietus , which is still its generally-accepted scientific name today.

Lactarius vietus - Grey Milkcap, Somerset UK

Synonyms of Lactarius vietus include Agaricus vietus Fr., Galorrheus vietus (Fr.) P.Kumm., Lactarius trivialis var. gracilis Peck, Lactarius varius Peck, Lactifluus varius (Peck) Kuntze, Lactifluus vietus (Fr.) Kuntze, Lactifluus parvus (Peck) Kuntze, Lactarius parvus Peck, Lactarius paludestris Britzelm., and Lactarius vietus var. paludestris (Britzelm.) Killerm.


The generic name Lactarius means producing milk (lactating) - a reference to the milky latex that is exuded from the gills of milkcap fungi when they are cut or torn. The specific epithet vietus means shrunken or wrinkled.

Identification guide

Cap of Lactarius vietus


4 to 8cm in diameter, convex and then centrally depressed, the caps are pale purplish-grey or buff-grey and slimy when wet.

Beneath the cap cuticle, the flesh is white or pale buff and rather brittle.

Side view of Lactarius vietus - Grey Milkcap


Adnate or very shortly decurrent, the crowded gills are white or pale yellow, turning brown when bruised.

When damaged, the gills release white milk that dries smoke-grey on the gills.


5 to 10mm in diameter and 5 to 7cm tall, the stems are smooth and cylindrical; they are rather brittle and easily broken.

Spores of Lactarius vietus - Grey Milkcap


Subspherical to broadly ellipsoidal, 7-9.5 x 5.5-7.5 µm; ornamented withwarts and ridges up to 0.8um tall that form a partial and often well-developed closed mesh or reticulum.

Show larger image

Spore print

Pale cream, but rather variable in tone.


No distinctive odour; hot and peppery taste.

Habitat & Ecological role

The Grey Milkcap is yet another of the milkcaps that form mycorrhizal associations with birch trees. It is most commonly found in damp, shady places.


August to October in Britain and Ireland.


Fairly frequent; often in quite large groups.

Similar species

Lactarius blennius is often a greeny-grey colour with a cap banded by droplet-like blotches, and it is very slimy during wet weather.

Culinary Notes

Some authorities suggest that this drab, gregarious mushroom is edible provided it is boiled thoroughly... and so is corrugated cardboard, but there are better treats to be had after a fungus foray. Please note also that some sources list this milkcap as inedible and possibly poisonous.

Grey Milkcaps, Lactarius vietus, Wales UK

Reference Sources

Pat O'Reilly (2016). Fascinated by Fungi, First Nature Publishing

Jacob Heilmann-Clausen, Annemieke Verbeken, & Jan Vesterholt (1998). The Genus Lactarius (Fungi of Northern Europe—Vol. 2) The Danish Mycological Society.

Funga Nordica, Henning Knudsen and Jan Vesterholt, 2008.

Fungi of Switzerland, volume 6: Russulaceae, Kränzlin, F.

BMS List of English Names for Fungi.

Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers. (2008). Dictionary of the Fungi; CABI.

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.

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