Amanita verna

Fool's Mushroom
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Scientific classification
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Subclass:	Hymenomycetes
Order:	Agaricales
Family:	Amanitaceae
Genus:	Amanita
Species:	A. verna
Binomial name
Amanita verna (Bull.: Fr.) Lam.

Amanita verna
Mycological characteristics
	gills on hymenium
	cap is convex or flat
	hymenium is free
	stipe has a ring and volva
	spore print is white
	ecology is mycorrhizal
	edibility: deadly

Amanita verna, commonly known as the fool's mushroom, Destroying angel or the mushroom fool, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe in spring, A. verna associates with various deciduous and coniferous trees. The large fruiting bodies (i.e., the mushrooms) appear in summer and autumn; the caps, stipes and gills are all white in colour.

Initially described by the French botanist Jean Baptiste François Pierre Bulliard, the fool's mushroom's specific epithet verna is derived from its springtime fruiting habit.

Description

The fool's mushroom (Amanita verna), also known as the spring destroying angel or death angel, is a close relative of Amanita phalloides, the death cap, and a member of the mushroom genus Amanita. Amanita verna, like its close relative, belongs to the subfamily Phalloideae.

The fool's mushroom is pure white, all the way to the gills and the stem. This fungus, like all amanitas, has a volva. The fool's mushroom's cap is 5–10 centimetres (2–4 in) wide, and is about the same height.

This mushroom's lamellae is free and white, and the volva is bag-like and large. Its annulus is white and membranous, and A. verna also does not react with potassium hydroxide solution, unlike its relative Amanita virosa. The mushroom's spores are smooth and elliptical.

Habitat and season

The fool's mushroom grows in European woodlands and hardwood forests in springtime as the fungus' Latin name (Amanita verna or spring destroying angel) suggests.

Unlike various closely related poisonous amanitas, this mushroom is not known to occur in North America.

Toxicity

Closely related to other deadly pure white amanitas, the fool's mushroom is one of the most poisonous mushrooms in the world. Just like the death cap, it contains amatoxins, primarily alpha-amanitin, which can cause liver failure. While this mushroom also contains other poisons like phallotoxins, these toxins are not behind the fatal poisoning that this mushroom, as well as all members of the subfamily Phalloideae, causes.

This mushroom's toxicity and symptoms are similar, if not identical to that of the death cap. Like other members of the subfamily Phalloideae, the fool's mushroom has been implicated in a number of serious or fatal poisonings.

There are no negative symptoms from eating this fungus until 6–24 hours after ingestion. The first symptom is simply unease. Violent cramps and diarrhea follow. On the third day, the same symptoms repeat themselves, but while to many this may seem like a sign of recovery, most of the time it is simply a herald of the final onset of symptoms, which include kidney and liver failure due to amatoxins. At this point, drastic measures like liver transplants need to be taken, or the victim would most likely die.

The fatal dosage of this mushroom is around 30g (1 oz), though it is not recommended taking even the smallest amount of any deadly amanita, as the fatal dosage varies with the size of the person who consumes the mushroom.

Similar species

Edible species

Many edible species resembles this mushroom and other amanitas, which is why the consumption of amanitas accounts for 95% of all mushroom fatalities.

The edible mushroom Leucoagaricus leucothites very closely resembles the fool's mushroom. However, Leucoagaricus leucothites lacks a volva, unlike A. verna. Sometimes, the volva of A. verna is hidden under leaf litter or soil, raising the need to dig out rather than cut L.naucina from the ground, so as to prevent misidentification.

Various young edible Agaricus spp. closely resemble A. verna, such as the tasty field mushroom Agaricus campestris, Agaricus silvicola and Agaricus arvensis. While older specimens of these do not resemble A. verna, when these fungus are young, they do resemble A. verna. All of these mushrooms lack volvas, unlike their deadly lookalike.

Amanita caesarea, with its bright orange shade, does not resemble A. verna, while this fungus is in bulb stage, it is also pure white. Amanitas closely resemble each other in bulb stage.

Another group of mushrooms in the Volvariella genus are frequently mistaken for the deadly amanitas. Volvariella volvacea has often been mistaken for deadly amanitas, and most of the time, they are mistaken for a relative of the fool's mushroom, the death cap (Amanita phalloides). Volvariella speciosa looks very similar to the fool's mushroom, but with close examination, one would realise that V.speciosa has salmon gills, while the fool's mushroom has white gills. Like Amanita, Volvariella species have volvas, hence their name.

Amanitopsis vaginata, formerly Amanita vaginata, can be pure white, and thus sometimes looks nearly identical to the fool's mushroom. However, unlike all Amanita species, Amanitopsis species lack rings. However, the ring of A. verna may sometimes be eaten by worms, and thus may be missing.

While in bulb stage, A. verna, as well as its relatives, are commonly mistaken for the edible puffballs, like those form the Lycoperdon or Calvatia species. To prevent confusion, it is important to cut puffballs into half. If there is the outline of Amanita's cap and stem in the 'puffball', the mushroom is an amanita.

The fatal poisoning caused by the fool's mushroom and closely related species makes amateur mushroom hunters avoid any species similar to them, and buy them from a grocer instead. Unless one can truly be sure if the species he or she is digging is edible, one should never pick a similar mushroom.

Poisonous species

Of course, the other pure white amanitas, like the destroying angels (Amanita virosa, Amanita bisporigera, Amanita ocreata) closely resemble Amanita verna. However, unlike Amanita verna, Amanita virosa stains yellow in KOH. Pure white specimens of the death cap also look like the fool's mushroom, and sometimes Amanita verna is considered a subspecies of Amanita phalloides.

Other toxic species of Agaricus, such as Agaricus xanthodermus, also resemble A. verna. However, Agaricus xanthodermus stains yellow if bruised, gives off a repulsive smell when cooked, and most importantly, lacks a volva.

List of similar species

Agaricus arvensis (Horse Mushroom)  : excellent edible

Agaricus campestris (Field mushroom)  : excellent edible

Agaricus silvicola (Wood mushroom)  : excellent edible

Agaricus xanthodermus (Yellow-staining mushroom)  : toxic or at least unpleasant-tasting (varies with consumer)

Amanita bisporigera (Destroying angel)  : deadly poisonous

Amanita caesarea (Caesar's Amanita) (bulb stage only) : excellent edible

Amanita ocreata (American destroying angel)  : deadly poisonous

Amanita phalloides (death cap)  : deadly poisonous

Amanita virosa (European destroying angel)  : deadly poisonous

Amanitopsis vaginata (Grisette)  : Edible

Calvatia spp. (Giant puffballs)  : (bulb stage only) : Mostly edible when young

Leucoagaricus leucothites : Edible and good, but can cause mild poisonings in some individuals

Lycoperdon spp. (Puffballs)  : Mostly edible when young

Volvariella speciosa : Edible but not tasty

Volvariella volvacea (Paddy straw mushroom) : Edible and good

See also

• Alpha-amanitin
• Amanitin
• List of Amanita species
• List of deadly fungi
• Mushroom poisoning