Earthy inocybe

Appearance

The cap is 1–4 cm in diameter and white or cream-coloured with a silky texture, at first conical before flattening out to a more convex shape with a pronounced umbo. The cap margins may split with age.

The thin stipe is 1–6 cm high and 0.3–0.6 cm thick and lacks a ring. The crowded gills are adnexed and cream early, before darkening to a brownish colour with the developing spores. The spore print is brown. The almond-shaped spores are smooth and measure around 9 × 5 μm. The faint smell has been likened to meal, damp earth, or even described as spermatic.

The variety ''lilacina'' is similar in shape but tinted lilac all over, with an ochre-brown flush on the cap umbo and the base of the stem. It has a strong mealy or earthy odour. This variety could be mistaken for the edible amethyst deceiver, although the latter species has a fibrous stipe, a fruity smell and lacks the ochre-coloured umbo.

Naming

It was first described as ''Agaricus geophyllus'' by mycologist Christian Hendrik Persoon in 1801, before being given its current binomial name in 1871 by Paul Kummer. Its specific epithet is derived from the Ancient Greek terms ''geo-'' “earth”, and ''phyllon'' “leaf”. A lilac form is known as var. ''lilacina''; it was originally described as ''Agaricus lilacinus'' by American mycologist Charles Horton Peck in 1872, before being given its current name by Claude Casimir Gillet in 1876.

Distribution

''Inocybe geophylla'' is common and widespread across Europe and North America. It is mycorrhizal, the fruiting bodies are found in deciduous and coniferous woodlands in summer and autumn. Within these locations, fruiting bodies may be found in grassy areas and near pathways, or often on rich, bare soil that has been disturbed at roadsides, and near ditches.

In Western Australia, Matheny & Bougher point to collections of what was referred to as ''I. geophylla'' var. ''lilacina'' by some Australian taxonomists, as a misapplication of the name ''I. geophylla'' var. ''lilacina''; the specimens have been reclassified as the species ''Inocybe violaceocaulis''.

Defense

Like many fibrecaps, ''Inocybe geophylla'' contains muscarine. The symptoms are those of muscarine poisoning, namely, greatly increased salivation, perspiration , and lacrimation within 15–30 minutes of ingestion.

With large doses, these symptoms may be followed by abdominal pain, severe nausea, diarrhea, blurred vision, and labored breathing. Intoxication generally subsides within two hours. Delirium does not occur.

The specific antidote is atropine. Inducing vomiting to remove mushroom contents is also prudent due to the speed of onset of symptoms. It is also dangerous to dose atropine, as that itself, can cause toxicity and death with too large or repeated doses.

Death has not been recorded as a result of consuming this species. It is often ignored by mushroom hunters because of its small size.