Amanita virosa

What You Should Know

Amanita virosa is a highly poisonous mushroom native to Europe. It has a white, egg-shaped appearance, with a white cap that may have a distinctive boss and white gills. The stem is thin, with a hanging ring, and the flesh is white. It grows in mixed oak-hardwood conifer forests, lawns, or grassy meadows near trees or shrubs. Symptoms of poisoning include vomiting, diarrhea, liver and kidney failure, and central nervous system damage.

The Amanita virosa fungus is dangerous because it resembles edible mushrooms such as Agaricus arvensis and Agaricus campestris, and puffballs before they have opened. The ability to peel the cap is often seen as a sign of edibility, but it is a deadly mistake in this species.

It is interesting to note that snails and maggots also like to infest this fungus. However, it does not mean that the fungus is safe for humans to eat. Snails and maggots don't have a liver, only a midgut gland, so they don't suffer from liver damage. Maggot or snail infestation is not a sign of non-toxicity. Even if animals such as deer, rabbits, and pigs eat these mushrooms, they have different enzymes that break down the poison differently in their bodies and neutralize it.

Other names: Death Angel, Destroying Angel, Netherlands (Kleverige knolamaniet), German (Kegelhütiger Knollenblätterpilz), Czech Republic (Muchomůrka jízlivá).

Amanita virosa Mushroom Identification

1. Cap

   The cap size ranges from 0.98 to 4.72 inches (2.5 to 12 cm) and has a shape that starts as almost oval and becomes convex, then broadly convex to somewhat bell-shaped or flat with age. It is bald and can be dry or slightly sticky, with a color that is stark white to ivory, sometimes discoloring towards the center or rarely yellowish or pinkish with maturity. The margin is not lined.

2. Gills

   Are quite close, pure white to cream, with a flocculose edge. The short gills are truncate.

3. Stem

   1.97 to 4.72 inches (5 to 12 cm) high and 0.31 to 0.59 inches (0.8 to 1.5 cm) in diameter, with a cylindrical shape and white color. It can be solid or pithy-hollow and has scaly rings below the ring, arranged in concentric rings and sometimes overlapping. The ring is white to yellowish, membranous, and collapses rapidly on the stem. The volva is white and sometimes pinkish, arising from the bulb and collapsing against the stem base. The flesh is pure white and does not change.

4. Flesh

   The flesh is fragile, white, when mature it has an unpleasant radish or raw potato taste.

5. Odor

   Not distinctive in young specimens, but often becoming foul and unpleasant (sickly sweet, or reminiscent of rotting meat) with old age.

6. Spores

   Spherical or subglobose, 7-8μm in diameter.

7. Spore Print

   White.

8. Habitat

   Grows in mixed woodlands, especially with beech trees, lawns, grassy meadows near trees or shrubs, on the mossy ground from summer to autumn. It forms a relationship with tree roots and is found in Europe and eastern Asia. It grows best on acidic soils and has been found under beech, chestnut, pine, spruce, and fir trees.

9. Chemical Reaction

   This species turns bright yellow on all surfaces when exposed to a 10% KOH solution.

Amanita virosa Look-Alikes

1. Agaricus sylvicola

   The gills turn grayish-pink and then chocolate brown as the spores mature.

2. Amanita phalloides

   Has a yellow cap.

3. Amanita verna

   Also deadly poisonous and very similar mushroom.

4. Amanita citrina

   Has a distinct ring without frayed belts underneath and a round tuber at the base of the stem. It lacks a pouch and has a raw potato scent. The spores are larger and amyloid.

5. Amanita strobiliformis

   This fungi is more fleshy and has a different cap shape, with a permanent velum remaining on the cap.

Amanita virosa Toxin Effects

The death angel mushroom contains a toxic protein called alpha-amanitin. This toxin attacks the liver's RNA polymerase enzyme and eventually impacts the central nervous system and kidneys. Symptoms of alpha-amanitin poisoning appear 6-24 hours after ingestion and can include discomfort, cramps, and diarrhea. If left untreated, the toxin can cause severe liver and kidney damage leading to death, unless a liver transplant or other drastic measures are taken.

The same toxin is, coincidentally, found in a completely unrelated mushroom Galerina marginata.

Amanita virosa Taxonomy and Etymology

The destroying angel is a poisonous white Amanita mushroom found in Europe, eastern North America, and the west, known as A. virosa, A. bisporigera, and A. ocreata, respectively. The name "virosa" means "toxic" in Latin and was given by Elias Magnus Fries, but it is debated if all white destroying angels in North America belong to A. bisporigera or other rarer species.

Amanita virosa Synonyms and Varietes

• Agaricus virosus Fr., 1838

• Agaricus virosus var. virosus Fr. 1838

• Amanita phalloides var. virosa (Lamarck) Sartory & L. Maire

• Amanita venenosa var. alba Gillet (1874)

• Amanita verna Rea (1922)

• Amanita virosa var. aculeata Voglino (1894)

• Amanita virosa var. levipes Neville & Poumarat (2004)

• Amanitina virosa (Bertill.) E.-J. Gilbert (1940)

Sources:

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