Fool's mushroom

Description

The fool's mushroom is an entirely white mushroom with a cap 5–10 cm across, with white, free gills, a drooping ring and a bulbous stem base set in a sac-like volva. The volva must be dug out, because it is often hidden in the leaf litter.

It grows in deciduous woods and parks, especially under oaks, from May or June to August. According to some descriptions it does not occur in Poland, and specimens of other white amanitas were formerly described under this name; others regard it as a species rare in southern Poland.

It is easily confused with young field mushrooms, and also with the destroying angel and the white form of the death cap (all deadly poisonous). Do not pick white gilled mushrooms without being sure of the species; the poison cannot be removed in the kitchen.

Identification features

Cap

Diameter about 5–10 cm. White or cream, surface smooth or slightly fibrous, occasionally with veil remnants. Ovoid or hemispherical when young, convex or flat when mature; margin smooth, pointed.

Hymenophore (underside of the cap)

Gills white, free (not attached to the stem), with smooth or flocculose edges. Sometimes described as widely spaced.

Stem

Height about 7–10 (up to 12) cm, diameter about 1–1.5 cm; whitish to greenish, often with a zigzag pattern and a flocculose surface, almost cylindrical, slightly tapering upwards. Ring white, drooping, grooved, often torn; stem smooth above it. Base bulbous with a sac-like volva, yellowish in older fruiting bodies.

Flesh

White. Smell sweetish, taste sometimes described as nutty — it must never be tested; do not taste the flesh of any suspicious mushroom. Reaction with KOH (20%): descriptions give different results — turns yellow or does not change colour (variety decipiens from southern Europe — orange-yellow).

Spore print and spores

Spore print white. Spores white, roundish to ellipsoid, smooth, amyloid, 8–10 × 7–9 µm.

Habitat and distribution

Ecology. Mycorrhizal fungus. Grows in deciduous woods and parks, especially under oaks; more broadly described from deciduous woods and from under trees of various species.

Distribution. Northern Hemisphere: Europe, Japan; occurrence in North America is disputed. Rare in Poland, mainly in the south; some descriptions state that it does not occur there and that old Polish reports concerned white specimens of the destroying angel or the death cap — the discrepancy needs to be resolved. Not legally protected.

Fruiting. In Central Europe from June to August, in southern Europe from May (descriptions also give spring).

What can it be confused with?

• Amanita virosa (destroying angel) — Cap less conical; in the KOH test it gives an orange-yellow reaction, while A. verna gives a yellow one. Both are deadly poisonous.
• Amanita phalloides var. alba (white form of the death cap) — Does not give a yellow reaction with KOH, unlike A. verna; difficult to tell apart in the field, also deadly poisonous.
• Agaricus spp. (field mushrooms, especially A. campestris, young fruiting bodies) — In young field mushrooms the gills are at first white, later turning pink and darkening; the amanita has white gills, a white spore print, a ring and a volva at the base of the stem. As early as 1780 Bulliard warned against confusing it with the field mushroom.
• Amanita citrina (false death cap), Amanita gilbertii, the thick-sheathed amanita — Sometimes confused; 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 name verna means "of spring" in Latin; in English the species is also called the "spring destroying angel".
• In 1780 Bulliard warned that it could easily be confused with the field mushroom, and described the "remedies" of the time (including ether in wine, garlic in milk), which are not effective treatment.
• HPLC analyses showed higher concentrations of alpha- and beta-amanitin than in the death cap, which makes it potentially the most poisonous amanita.
• According to some descriptions the species does not occur in Poland, and old Polish records concerned other white amanitas.