King of Sweden Amanita

Description

The royal fly agaric is a large mushroom with a liver-brown, glossy cap (5–25 cm), covered with ochre-yellow patches arranged in regular circles. The gills are white and later creamy-yellowish, the stem whitish-yellow with a distinct yellowish ring and a bulb decorated with rows of yellow warts.

It is rare in Poland and has the status of a vulnerable species. It grows from June to September, more often in the mountains, in coniferous woods, on the ground among grasses, especially under firs.

It resembles the blusher and the grey spotted amanita, but differs in its yellow patches and yellowish flesh under the skin. It is a poisonous mushroom, with an effect similar to the fly agaric. Because of its rarity it is best left in the forest. If you are not sure of the species, do not pick it and do not eat it.

Identification features

Cap

Diameter 5–25 cm (descriptions also give 10–25 cm); at first hemispherical, surrounded by a veil, then increasingly spread out. Surface dry, glossy, liver-brown to yellowish-brown, darker at the top, covered with fairly regular, concentrically arranged ochre-yellow patches (veil remnants). In older specimens the margin is striate (for 1.5–2 cm); the skin can be peeled almost to the centre.

Hymenophore (underside of the cap)

Gills free, crowded, white, later creamy-yellowish; edges fringed. In young specimens covered by a yellowish veil.

Stem

Height 8–20 cm, thickness 1.5–3.5 cm, cylindrical, brittle, smooth, white or yellowish-white. Ring distinct, yellowish. Base with a bulb bearing 2–4 rows of rings of warts (veil remnants), lemon or ochre-yellow; no sac-like volva.

Flesh

Yellowish-brown to golden yellow under the cap skin, slightly yellowish in the stem, white elsewhere; does not change colour when damaged. Smell and taste weak. The taste must not be tested; do not taste the flesh of this or any suspicious mushroom.

Spore print and spores

Spore print white. Spores broadly ellipsoid to almost spherical, hyaline, smooth, non-amyloid, 9–12 × 7–8 µm.

Habitat and distribution

Ecology. Mycorrhizal fungus; experimentally forms mycorrhiza with birch, Scots pine, mountain pine and spruce. Grows on the ground among grasses, in mountain woods, especially under firs and spruces, in coniferous woods (according to some descriptions also in deciduous ones). Fairy rings have been described.

Distribution. Occurs only in some countries of Europe; more frequent in the north (Scandinavia), not recorded in the south and west of Europe; also reported from Germany, Hungary, Latvia, Russia, Slovakia and Korea, and in North America only from Alaska. In Poland rare, montane; on the Red List of Plants and Fungi of Poland (2006) it has status V — vulnerable; it is also on threatened lists in Germany and Lithuania. Not legally protected.

Fruiting. From June to September.

What can it be confused with?

• Amanita muscaria (fly agaric) — The royal fly agaric has no red cap colour at all, and has yellow patches/rings on the stem.
• Amanita rubescens (the blusher) — Pale specimens of the royal fly agaric may resemble it; the blusher takes on a flesh-pink tint when damaged, and the flesh under the skin is white (yellowish in the royal fly agaric).
• Amanita excelsa (grey spotted amanita) — Cap greyish-brown without yellow patches, gills white, ring notched and white.
• Amanita pantherina (panther cap) — Similar colour, but the flesh under the skin is white, and the bulb is cup-shaped with a distinct rim.
• Macrolepiota procera (parasol mushroom) — In a Finnish poisoning case three people thought they had eaten parasol mushrooms; the parasol has a movable ring and a snake-like pattern on the stem.

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 Latin name regalis means "royal"; in Sweden it is known as king of Sweden Amanita, and in Germany as Königsfliegenpilz.
• In 2000 the German Mycological Society chose it as Mushroom of the Year.
• It is a vanadium bioaccumulator: in Scandinavian specimens 38–169 mg/kg dry weight was found, whereas in most mushrooms it is below 2 mg/kg.
• Formerly regarded as a variety of the fly agaric (A. muscaria var. regalis); in 2006 molecular studies by Geml et al. suggested that it is only a polymorphism of that species, but nomenclatural registers still recognise it as a separate species.