Amanita phalloides

What You Should Know

Amanita phalloides is a deadly poisonous basidiomycete fungus in the genus Amanita. Widely distributed across the world. Important field characters are the smooth, yellowish-green to yellowish-brown cap, sometimes with a thin, appressed white universal veil patch, usually non-striate cap margin, free, cream-colored gills, normally solid, not hollow stipe, pendulous annulus, and thin, white, membranous, sac-like volva.

It is found widely in coastal areas as well as inland at low elevations. A rare, white form of this mushroom, var. alba resembling the Death Angel of the Eastern U.S (Amanita bisporigera), also occurs in the California. Another lethal Amanita found locally is Amanita ocreata. Cream-colored, and similar in appearance to the Death Cap, it fruits under coast liveoak (Quercus agrifolia) during the spring.

Deathcaps can produce circles of fruiting bodies, known as fairy rings, which over centuries have been the subject of fairy tales and folklore.

Other names: Death Cap, Stinking Amanita, Deadly Amanita, Muchomůrka Zelená (Czech Republic).

Amanita phalloides Mushroom Identification

1. Cap

   4-16 cm; nearly round or oval at first, becoming convex, then broadly convex to flat in age; bald; sticky when wet, shiny when dry; color ranging from dull green to olive to yellowish to brownish (rarely, white "albino" forms are collected alongside forms with pigmented caps); appearing finely and innately streaked; occasionally with one or a few patches of white veil material; the margin usually not lined.

2. Gills

   Free from the stem or nearly so; white (sometimes with a slight greenish tint); close or crowded.

3. Stem

   5-18 cm long; 1-2.5 cm thick; more or less equal, or frequently tapering to apex and flaring to a swollen base; bald or finely hairy; white or with tints of the cap color; with a white, skirtlike ring that typically persists but is sometimes lost; with a sacklike white volva encasing the base (sometimes underground or broken up).

4. Flesh

   White throughout; unchanging when sliced.

5. Spores

   The spores measure (7.5-) 8.0 - 10.1 (-13.5) × (5.5-) 6.1 - 8.0 (-10.5) µm and are subglobose to broadly ellipsoid to ellipsoid and amyloid. Clamps are not found at bases of basidia.

6. Spore Print

   White.

7. Odor and Taste

   In age, the odor of this mushroom is distinctively repugnant and can be detected at a distance. It is various described as "sickeningly sweet," "like rotten honey," "like carrion," etc.

8. Habitat

   Solitary, scattered, to gregarious under coast liveoak (Quercus agrifolia), occasionally with other oaks and ornamental hardwoods; fruiting sporadically during the summer months in watered areas or from fog drip along the coast; common from early fall to mid-winter.

Amanita phalloides Look-Alikes

1. Agaricus campestris

   Do not have volvae. The gills of immature mushroom is not gray or pinky-brown indeed to young young Agaricus mushrooms.

2. Amanita citrina

   Smells strongly of raw potatoes and has brownish-cream veil fragments on the cap.

Amanita phalloides Symptoms

1. Gastric-intestinal troubles (nausea, alimentary vomiting, then biliary, watery diarrhea), dehydration with consequent hypotension, strong thirst, abdominal pains.

2. Apparent improvement.

3. Acute hepatic insufficiency and appearance of icterus, coagulopathy, at times serious dehydration with acute renal insufficiency, lethargy, coma, and possible death. In any case, as a consequence of the acute hepatic insufficiency, the liver might be irreversibly jeopardized, to the point to necessitate transplantation.

Amanita phalloides Treatment

Any patient suspected of ingesting death cap mushrooms should be admitted to the hospital.

Initial management consists of vigorous monitoring and replacement of expected fluid losses, which may be several liters per day. Along with fluid replacement correction of metabolic disturbances such as acidosis, hypoglycemia, and electrolyte imbalances should be undertaken. The patient should be hemodynamically monitored and biochemical parameters followed closely.

Amanita phalloides Toxin

This species contains three major toxoids: amatoxins, phallotoxins, and virotoxins. Among them, amanita toxins, especially α-amanita, are the main cause of toxic effects on the human body. Alpha-amanitamin is known to inhibit RNA polymerase II, resulting in protein deficiency and eventual cell death, but other mechanisms are believed to be involved.

The liver is the main target organ for toxicity, but other organs are also affected, especially the kidneys. Symptoms of poisoning usually appear after an incubation period and may include gastrointestinal distress, followed by jaundice, seizures, and coma, leading to death. Treatment includes supportive measures, gastric cleansing, medication, and finally, liver transplantation if the clinical condition worsens.

The discovery of an effective antidote remains a major unsolved problem. Antidotal perspectives will be raised as to set the pace to new and improved therapy against these mushrooms.

Amanita phalloides Taxonomy and Etymology

In 1727 French botanist Sébastien Vaillant described this species and gave a succinct phrase name "Fungus phalloides, annulatus, sordide virescens, et patulus" - a recognizable name for the fungus today.

In 1821 Elias Magnus Fries described it as Agaricus phalloides, but included all white amanitas within its description.

In 1833, Johann Heinrich Friedrich Link settled on the name Amanita phalloides, after Persoon had named it Amanita viridis 30 years earlier. Although Louis Secretan's use of the name A. phalloides predates Link's, it has been rejected for nomenclatural purposes because Secretan's works did not use binomial nomenclature consistently; some taxonomists have, however, disagreed with this opinion.

The scientific name phalloides means "phallus-shaped", it is unclear whether it is named for its resemblance to a literal phallus or the stinkhorn mushrooms Phallus.

Amanita phalloides Synonyms

1. Venenarius phalloides ( Fr.) Murrill, 1912

2. Amanitina phalloides (Fr.) E.-J. Gilbert, 1940

3. Fungus phalloides Vaill.

4. Agaricus phalloides Vaill. ex Fr.

5. Amanita viridis Pers.

6. Amanita phalloides Secr. (nomen nudum) nud.

Sources:

Photo 1 - Author: Daniel Neal from Sacramento, CA, US (Creative Commons Attribution 2.0 Generic)

Photo 2 - Author: Michel Langeveld (Creative Commons Attribution-Share Alike 4.0 International)

Photo 3 - Author: Michel Langeveld (Creative Commons Attribution-Share Alike 4.0 International)

Photo 4 - Author: Michel Langeveld (Creative Commons Attribution-Share Alike 4.0 International)

Photo 5 - Author: misspril (Creative Commons Attribution-Share Alike 4.0 International)