Inocybe geophylla var. lilacina (Peck) Gillet - Lilac Fibrecap

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

Distribution - Taxonomic History - Etymology - Identification - Toxicity - Reference Sources

Inocybe geophylla is a very common species and its white variety is sometimes mistaken for small field mushrooms (Agaricus campestris) with disastrous results: it is very poisonous and its consumption can be fatal.

Although it is known to be mycorrhizal with deciduous broadleaf trees and with conifers, this little lilac-coloured mushroom is also a very common find on damp disturbed roadside mud that is rich in leaf litter.

Distribution

Inocybe geophylla var. lilacina is a common and widespread woodland species throughout Britain and Ireland. These toxic little toadstools are found in most parts of mainland Europe, and they are also recorded as common in North America.

Taxonomic history

This poisonous mushroom owes its scientific basionym to American mycologist Charles Horton Peck (1833 - 1917) who, in 1873, gave it the scientific name Agaricus geophyllus var. lilacinus. Three years later, in 1876, French mycologist Claude-Casimir Gillet (1806 - 1896) renamed it Inocybe geophylla var. lilacina, its currently-accepted scientific name.

Synonyms of Inocybe geophylla var. lilacina include Agaricus geophyllus Sowerby, Gymnopus geophyllus (Pers.) Gray, Agaricus geophyllus var. violaceus Pat., Inocybe geophylla var. violacea (Pat.) Sacc., and Inocybe lilacina (Peck) Kauffman.

Toxicity

Inocybe geophylla is a deadly poisonous and fairly common species that grows in habitats where people expect to find edible mushrooms. That makes it very dangerous indeed. The symptoms of poisoning by this and several similar Inocybe species are those associated with muscarine poisoning. Excessive salivation and sweating set in within half an hour of eating these fungi. Depending on the amount consumed, victims may also suffer abdominal pains, sickness and diarrhoea, together with blurred vision and laboured breathing. Deaths of otherwise healthy people from eating these fungi are not reported. Anyone with a weakened heart or with respiratory problems is much more at risk. The lilac variety is no less toxic that its white close relative; it is a deadly poisonous mushroom and care is needed to ensure that this toxic toadstool is never included among other violet or purplish fungi (such a Lepista nuda, the Wood Blewit) that are being collected for human consumption.

Etymology

Inocybe, the genus name, means 'fibrous head', while the specific epithet geophylla is derived from the Ancient Greek words geo- meaning earth, and phyllon which means leaf. It hardly needs mentiolning that the variety name lilacina is a reference to the lilac colouring on the caps of these little mushrooms.

Identification guide

	Cap The smooth, silky cap has a diameter of 1.5 to 3.5cm; initially conical, it flattens as it  matures, usually retaining a pointed umbo and streaky radial fibres that in dry weather tend to tear into strips towards the edge of the cap. The cap is initially lilac but fade to ochre-brown from the centre as the fruitbody ages.
	Gills The crowded gills, which are notched or adnexed, start off creamy-grey and later turn clay-brown as the spores mature. Stem 3 to 6mm in diameter and up to 6cm tall, the stipe is smooth and silky, sometimes slightly fibrillose towards the base, and the same colour as the cap. The stipe also gradually turns clay-brown with age.
	Spores Ellipsoidal, smooth, 7.5-10 x 4.5-5.5μm. Show larger image Spores of Inocybe geophylla var. lilacina  X  Spore print Dull brown.
Odour/taste	Slightly earthy or mealy smell. Reported to have a mild taste (but please be aware that this is a deadly poisonous fungus and so tasting any part of it is not advisable).
Habitat & Ecological role	Beside paths and on roadside verges beneath deciduous trees and in mixed woodland; less frequently under conifers.
Season	Summer and autumn.
Similar species	Amethyst Deceiver, Laccaria amethystina has violet gills but is otherwise very similar in appearance to Inocybe geophylla var. lilacina.

Reference Sources

Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Alan Outen and Penny Cullington (2009), Keys to the British Species of Inocybe.

Funga Nordica: 2nd edition 2012. Edited by Knudsen, H. & Vesterholt, J. ISBN 9788798396130

BMS List of English Names for Fungi

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.

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