Amethyst Deceiver

Description

The amethyst deceiver is a small mushroom with a cap 2–6 cm across, deep violet in wet weather and fading to whitish-violet in dry weather. The gills are thick, widely spaced, violet, and remain violet even when the rest of the fruiting body fades. The stem is thin, fibrous, hollow, the colour of the cap.

It grows in broadleaf and coniferous forests, most often under beeches, and also in parks and gardens, from late summer to early winter. It is common in Poland. The colour varies greatly, so it is easy to overlook after rain or in drought.

It can be confused with violet poisonous mushrooms, e.g. the lilac variety of the lilac fibrecap (unpleasant smell, umbo) and the lilac bonnet (radish smell). If you are not sure, do not pick or eat it.

Identification features

Cap

Diameter 2–6 cm; young hemispherical or bell-shaped with an inrolled margin and a depression in the centre, then arched, finally flat and funnel-shaped with a wavy margin. Hygrophanous. Surface smooth, delicately scaly in mature ones, margin slightly grooved. In wet weather violet or brown-violet, in dry weather or in older specimens whitish-violet.

Hymenophore (underside of the cap)

Gills thick, widely spaced, often wavy, broadly attached or slightly decurrent or sinuate. Violet in young ones, later dusted whitish with spores; even when the fruiting body is faded, the gills remain violet.

Stem

Height 0.6–12 cm (descriptions give different ranges), thickness 3–10 mm, hollow, fibrous, slightly thickened below; colour as the cap, with whitish fibrils at the base. No ring.

Flesh

Watery, thin; slightly violet in wet weather, pinkish-brown in dry weather; smell and taste indistinct. Do not taste the flesh as an identification feature.

Spore print and spores

Spore print white. Spores spherical, colourless, spiny-warty, about 7–10 µm in diameter.

Habitat and distribution

Ecology. A mycorrhizal fungus, with broadleaf and coniferous trees, most often with trees of the order Fagales, e.g. with beech. According to some descriptions it also grows on rotting wood. It is a nitrophilous fungus (a so-called “ammonia fungus”) — it grows most abundantly on soils rich in nitrogen compounds.

Distribution. Widely distributed: Asia, Europe, North and Central America, New Zealand. Common in Central Europe, including Poland. Grows in forests, gardens and parks. It is not legally protected in Poland.

Fruiting. From late summer to early winter; in Europe about June–December.

What can it be confused with?

• Mycena pura (lilac bonnet) — Considered poisonous. The fruiting body is less slender in the deceiver; the bonnet has a characteristic radish or turnip smell.
• Inocybe geophylla var. lilacina (lilac fibrecap, lilac variety) — Poisonous. Has an umbo on the cap and an unpleasant smell.
• Laccaria laccata (deceiver) — Also fades and weathers, which makes identification difficult; detailed differences — no data.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The English name “amethyst deceiver” comes from the fact that the intense violet fades with age and under the influence of weather, which makes identification difficult.
• The species was described in 1778 by William Hudson as Agaricus amethystinus.
• It is a so-called ammonia fungus, fruiting abundantly on nitrogen-rich soils.
• It can bioaccumulate arsenic from contaminated soil.