Lactarius subdulcis (Pers.) Gray - Mild Milkcap

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

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

Another of the small milkcaps commonly found in broadleaf woods, Lactarius subdulcis is mycorrhizal with Beech trees, but it also occurs under birches and occasionally under deciduous oaks. This is a difficult milkcap to identify with certainty because is has so many lookalikes.

Distribution

Very common in Britain and Ireland as well as on mainland Europe, Lactarius subdulcis is not recorded in North America.

Caps of Lactarius subdulcis store abundant, sweet-tasting white milk.

Taxonomic history

The Mild Milkcap was described in 1801 by Christiaan Hendrik Persoon, who gave it the binomial scientific name Agaricus lactifluus var. subdulcis. (Vast numbers of gilled fungi were dumped into the Agaricus genus in the early days of fungal taxonomy; most have since been moved to other genera leaving in the present-day Agaricus genus a much smaller number of gilled mushrooms that are sometimes referred to as the 'true mushrooms'.) It was British mycologist Samuel Frederick Gray (1766 - 1828) who in 1821 transferred this species to the genus Lactarius and raised it to full species status as Lactarius subdulcis.

Synonyms of Lactarius subdulcis include Agaricus lactifluus var. subdulcis Pers.

Etymology

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 subdulcis literally means 'under sweet' - a reference to the initial mild then sweet taste that is later followed by a slight bitterness.

Identification guide

	Cap Variable from reddish-brown to dark cinnamon with a paler buff margin; convex, centre becoming depressed with a small umbo; 3 to 7cm across.
	Gills White maturing to a pinkish buff; adnate or slightly decurrent; moderately crowded. Latex is white, unchanging; abundant; taste initially mild, becoming slightly bitter. Stem Slightly paler than the cap but much lighter at the apex; cylindrical, base slightly clavate; 4 to 7cm long, 0.6 to 1.3cm diameter; no stem ring.
	Spores Ellipsoidal, 7.5-9.5 x 6.5-8µm; ornamented with warts up to 1µm tall joined by narrow ridges to form a well-developed network. Spore print Cream with a slight salmon-pink tinge.
Odour/taste	No significant odour; taste initially mild and then sweet but eventually becoming slightly bitter and acrid.
Habitat & Ecological role	Mycorrhizal, under Beech trees and occasionally other hardwoods.
Season	August to November in Britain and Ireland.
Occurrence	Very common in Britain and Ireland as well as on mainland Europe, Lactarius subdulcis is not recorded in North America.
Similar species	Lactarius blennius, the Beech Milkcap, is much greyer.

Culinary Notes

Lactarius subdulcis is edible but it is not highly regarded because many superior, larger and more plentiful milkcap mushrooms fruit at the same time of the year in the same deciduous woodland habitats preferred by the Mild Milkcap.

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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