Lactarius rufus (Scop.) Fr. - Rufous Milkcap

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

Lactarius rufus - the Rufous Milkcap

Lactarius rufus, the Rufous (meaning foxy red) Milkcap, is found in great abundance beneath spruce, pine and occasionally birch trees in areas where the soil is acidic. The milk (latex) is very strong and acrid tasting, which makes this milkcap one of the hottest of all mushrooms.

Taste testing is an important step in identifying milkcap mushrooms, but for red-brown species such as this taste only a little piece or your tongue might explode!

Lactarius rufus - the Rufous Milkcap, in the New Forest, Hampshire UK

Distribution

Widespread and common throughout Britain and Ireland, the Rufous Milkcap is also found in most parts of mainland Europe. Very similar milkcaps occur in North America but when someone gets around to comparing the DNA sequences they may turn out not to be co-specific with the European species Lactarius rufus.

Taxonomic history

The Rufous Milkcap was described in 1772 by Scopoli, who established the basionym of this species when he gave it the scientific name Agaricus rufus. (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'.)

Lactarius rufus - the Rufous Milkcap, in spruce woodland, West Wales

It was the Swedish mycologist Elias Magnus Fries who in 1838 transferred this milkcap to the genus Lactarius, thereby establishing its scientific name as Lactarius rufus, which is still the binomial name by which it is generally referred to by mycologists today.

Synonyms of Lactarius rufus include Agaricus rufus Scop., Lactarius rufus var. exumbonatus Boud., and Lactarius mollis D.A. Reid.

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 rufus is a Latin adjective that translates as rufous, meaning a foxy reddish-brown colour.

Identification Guide

Rufus milkscap showing gills and latex

Cap

4 to 10cm in diameter, the dark reddish-brown caps are dry and have a finely matt surface; slightly sticky in wet weather. Convex at first, the caps become funnel-shaped as the fruiting body matures. There is often a small central umbo once the cap has expanded and become funnel shaped.

Gills of Lactarius rufus

Gills

The pale reddish-cream gills are weakly decurrent and crowded. As they mature, the gills tend to become blotchy.

When the gills of this milkcap are damaged, a watery-white latex is released; its taste is initially mild but later becomes very hot and acrid.

Stem

5 to 20mm in diameter and 4 to 9cm tall, the stems are smooth and the same colour as the cap or a little paler. There is no stem ring.

 

 

Spores

Broadly ellipsoidal, 6.5-9 x 5.5-6.5μm, hyaline; ornamented with a well-developed and almost complete network of ridges.

Spore print

Pale cream with a slight salmon pink tinge.

Odour/taste

No distinctive odour but a mild taste that soon becomes very hot and acrid.

Habitat & Ecological role

Coniferous woodland, usually under pines; occasionally under birches.

Season

August to November in Britain and Ireland.

Similar species

Lactarius subdulcis is a smaller milkcap sometimes of similar coloration; it occurs under beech trees.

Culinary Notes

Although according to David Arora the Rufous Milkcap has been harvested commercially in Scandinavia and Russia for many years, most western field guides and other sources of culinary guidance - Class this as an inedible mushroom. It is sometimes dried and powdered (after thorough cooking) for use as a seasoning.

Lactarius rufus - the Rufous Milkcap, in spruce woodland, Wales

Reference Sources

Fascinated by Fungi, Pat O'Reilly, 2011

Funga Nordica, Henning Knudsen and Jan Vesterholt, 2008.

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

BMS List of English Names for Fungi.

Arora D. (1986). Mushrooms Demystified: a Comprehensive Guide to the Fleshy Fungi. Berkeley, California: Ten Speed Press. ISBN 0-89815-169-4.

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.

Acknowledgements

This page includes pictures kindly contributed by David Kelly.

Top of page...


Fascinated by Fungi, 2nd edn, hardback

If you have found this information helpful, we are sure you would also find our book Fascinated by Fungi by Pat O'Reilly very useful. Author-signed hardback copies at a special discount price are available here...

Other nature books from First Nature...