Fly agaric

Description

The fly agaric is one of the most recognisable mushrooms: large (cap up to 20 cm), usually bright red, covered with white or whitish-yellow patches. It has white, free gills and a white stem with a hanging ring and a bulbous base with rows of rims, without a distinct volva. The flesh is white and does not change colour.

Very common in Poland, it grows from June to November in deciduous, coniferous and mixed woods, especially often under birches, forming mycorrhiza with them. It is found across the whole Northern Hemisphere, and humans have also introduced it to the Southern Hemisphere.

Although it is easy to recognise, it is sometimes confused with the royal fly agaric, Caesar's mushroom (in warm countries), red brittlegills or yellow varieties. It is a poisonous mushroom and must not be eaten. If you are not sure of the species, do not pick it and do not eat it.

Identification features

Cap

Diameter up to 20 cm; spherical in very young specimens, then hemispherical, low-domed, flat and slightly depressed in the centre in older ones. Surface smooth, sticky when wet, delicately notched at the margin in older specimens. Most often bright red (in East Asian, North American and some European forms also orange, yellow or white). At first covered with a whitish veil, whose remnants remain as white or whitish-yellow patches.

Hymenophore (underside of the cap)

Gills white or pale yellowish, ventricose, crowded, free (not attached to the stem).

Stem

Height up to 20 cm, thickness up to 3 cm, cylindrical, easily breaking off, solid when young, then hollow; white or yellowish. Ring hanging, white (sometimes yellowish). Base bulbous, surrounded by several rows of roll-like swellings (veil remnants), without a distinct volva.

Flesh

White (sometimes yellowish under the cap skin), brittle, does not change colour when damaged; no smell, taste mild in the descriptions of the sources — it must not be tested; do not taste the flesh of this or any suspicious mushroom.

Spore print and spores

Spore print white. Spores smooth, ellipsoid, non-amyloid (do not stain with iodine); size 9–11 × 6–9 µm (descriptions also give 9–13 × 6.5–9 µm).

Habitat and distribution

Ecology. Ectomycorrhizal fungus with a long list of partners: birches (especially silver birch), firs, pines, spruces, aspens, oaks, as well as shrubs of the rockrose family and dwarf willows; in the Southern Hemisphere also southern beeches and eucalypts. Grows on the ground in deciduous, coniferous and mixed woods. Introduced with pine seedlings to many regions of the world.

Distribution. A cosmopolitan species, native to the temperate and boreal zones of the Northern Hemisphere (also at higher elevations in warmer regions, e.g. the Hindu Kush, the Mediterranean, Central America); introduced to Australia, New Zealand, South Africa and South America. In Central Europe, including Poland, very common. Not covered by species protection.

Fruiting. From June to November.

What can it be confused with?

• Amanita regalis (royal fly agaric) — Cap brown, without red; patches, dots and ring edge yellow; grows mainly under spruces/firs in the mountains. Also poisonous.
• Amanita caesarea (Caesar's mushroom) — Paler, orange-yellow cap without dots, yellow stem and gills, stem bulb in a volva; occurs in warm deciduous woods, mainly in southern Europe, where mistakes most often occur.
• Russula xerampelina (crab brittlegill) and other red brittlegills — Straight stem without a ring and other adornments, smooth cap.
• Amanita gemmata (gemmed amanita; also written A. junquillea) — Sometimes confused with the yellow varieties of the fly agaric; it is smaller and has a different stem structure.

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 comes from the old custom of crumbling it in milk as a fly killer; Albertus Magnus noted this before 1256. The insects are only intoxicated, not dead.
• Linnaeus described it in 1753 in "Species Plantarum", and gave information on the use of the fly agaric from Småland.
• It appeared on a Polish stamp from the "Mushrooms of Poland" series issued on 8 May 1959 (3.40 zł, triangular).
• It bioaccumulates vanadium (in the form of amavadine) at concentrations up to 400 times higher than in the soil.
• It is the inspiration for, among other things, the Smurfs' houses and games of the Mario series.