Laccaria bicolor (Maire) P.D. Orton - Bicoloured Deceiver

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Hydnangiaceae

Laccaria bicolor - Bicoloured Deceiver

Treated as merely a variety of Deceiver until relatively recent times, Laccaria bicolor is distinguished from the more common Deceiver Laccaria laccata and Scurfy Deceiver Laccaria proxima by its stem, which has a lilac-coloured base but a tawny upper section.

Distribution

Rather uncommon and localised in Britain and Ireland, Laccaria bicolor occurs also throughout mainland Europe and in North America.

Laccaria bicolor under a spruce tree

Taxonomic history

This woodland fungus was described in 1937 by the French mycologist René Maire (1878 - 1949) as a variety of the Deceiver and given the scientific name Laccaria laccata var. bicolor. Nearly a quarter of a century elapsed before British mycologist Peter Darbishire Orton (1916 - 2005) raised the status of this mushroom to species level, renaming it Laccaria bicolor.

Synonyms of Laccaria bicolor include Laccaria laccata var. bicolor Maire, and Laccaria proxima var. bicolor (Maire) Kühner & Romagn.

All Laccaria species are ectomycorrhizal fungi, forming symbiotic relationships with forest trees. Genetic research into Laccaria bicolor and other members of the little-understood family Hydnangiaceae is throwing new light on the complexities of these root-fungus relationships.

Etymology

The specific epithet bicolor is Latin and simply means 'being of two colours' - it's a two-tone toadstool.

Identification guide

Cap of Laccaria bicolor

Cap

Bicolour Deceiver caps are 2 to 6cm in diameter, initially convex becoming flat-topped at maturity, often with a depressed centre and a down-turned rim.

Hygrophanous: during wet weather young caps of Laccaria bicolor are deep tan or reddish-brown, but during dry spells the caps become much paler buff and eventually almost white. This colour change is a characteristic of fungi in this genus and the reason for their common name 'deceivers'.

Gills of Laccaria bicolor, the Bicolour Deceiver

Gills

The deep, broad pinkish-lilac (when young) gills of the Bicoloured Deceiver are widely spaced and interspersed with shorter gills; they are adnate or slightly decurrent. In normal autumn weather, before the caps fade the tan gills begin losing their colour and become clay-lilac and then buff. This is because they get covered in spores. (Surprisingly, when you consider how dark the young gills are - the spores of this mushroom are white.)

Stems of Laccaria bicolor

Stem

Laccaria bicolor stems are 5 to 10mm in diameter and 5 to 14cm tall. The tough, fibrous stems are more 'hairy' towards the base, where the lower part of the stems of fresh young specimens (left) are covered in a lilac-coloured mycelial down. Unfortunately, this lilac colouring soon fades, so that identification of older, more mature fruitbodies is more difficult. (The basidia of some Laccaria species are two-spored while others are four-spored, but to see these features you need to be skilled in using a high-powered microscope.)

Spores of Laccaria bvicolor

Spores

7 to 9.5 x 6 to 8.5μm, subglobose to broadly ellipsoidal, very spiny (spines up to 1.8μm tall), thick-walled, hyaline.

Show larger image

Spore print

White.

Basidia

Four-spored.

Odour/taste

Not distinctive.

Habitat & Ecological role

Ectomycorrhizal with pines and other conifers, Bicolour Deceivers are found among leaf litter in all kinds of mixed woodland and on heaths; they favour neutral to acidic soils.

Season

June to November in Britain and Ireland.

Similar species

Laccaria laccata appears in similar habitats but it does not have lilac down on the lower part of its stem.

Laccaria amethystina is a violet coloured member of the same genus; once it has dried out it becomes pale buff and virtually indistinguishable from dried out specimens of Laccaria bicolor and Laccaria laccata.

Culinary Notes

The Bicoloured Deceiver Laccaria bicolor is an edible mushroom. The caps are very good when fried, tasting rather like shop-bought button mushrooms (Agaricus bisporus). Bicolour Deceivers are also fine when used to make mushroom soup. The tough fibrous stems are best discarded.

Acknowledgements

This page includes photographs that are shown with the kind permission of David Kelly.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

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.

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