Amanita muscaria
Flora Scotland 2: 19. 1821.
Photo: Amanita muscaria var. flavivolvata
Common Name: fly agaric
Cap 6-39 cm broad, rounded at first, then plane in age, surface viscid when moist; margin striate often with adhering partial veil fragments when young; cap red, usually with white warts but in one variety, yellow warts.
Gills adnexed to free, white to cream, edges roughened.
Stipe white, 7-16 cm long, 2-3 cm thick, tapering to a bulbous base; partial veil membranous, breaking to form a superior skirt-like veil. Volva consisting of two to three concentric rings at the stipe base.
Spores 9-13 x 6.5-9.5 µm elliptical, smooth, nonamyloid. Spore print white.
In the California, Amanita muscaria occurs primarily under pines, especially Monterey and Bishop pine. Fruitings occur in early winter, and can be spectacular, with large groups or rings brightening the woods. The Fly Agaric shares the pine habitat with the much sought after King Bolete, Boletus edulis. Some mushroom hunters thus use Amanita muscaria as an indicator species.
Toxic when raw. Contains ibotenic acid and muscimol.
The toxins are water soluble. Many persons have eaten this fungus, without ill effect, after parboiling the sliced mushroom and discarding the liquid. For more edibility information, see Rubel & Arora, Economic Botany 62(3), 2008 (the printed article has a mistake...it states "250 g or 4 oz", which are not equivalent, correction from Arora):
"Cut the A. muscaria cap and stalk into thin slices (no more than 3-4 mm or 1/8" thick) to hasten dissolving of the active constituents. For each 110 g or 4 oz of mushroom, use 1 liter or quart of water with 1 teaspoon salt. Garlic and bay leaf can be added to the water for flavoring. Bring the water to a rolling boil, then add the sliced mushrooms. Begin timing the cooking once the water returns to a boil. Boil for 10-15 minutes, until the mushroom is soft, then drain and rinse."
With its bright red, sometimes dinner plate-sized caps, Amanita muscaria is one of the most striking of all mushrooms. The white warts that adorn the cap, white gills, well developed ring and distinctive volva of concentric rings separate the Fly Agaric from all other red mushrooms. There are several color varieties of A. muscaria in the U.S. ranging from red to orange, yellow and white, but only two occur commonly in the Bay Area, Amanita muscaria var. muscaria with a red cap and white warts, and A. muscaria var. flavivolvata, with a red cap and yellowish warts. Photo at top is variety flavivolvata.
Ammirati, J.F., Traquair, J.A. & Horgen, P.A. (1985). Poisonous Mushrooms of the Northern United States and Canada. University of Minnesota Press: Minneapolis, MN. 396 p.
Arora, D. (1986). Mushrooms Demystified. Ten Speed Press: Berkeley, CA. 959 p.
Benjamin, D.R. (1995). Mushrooms: Poisons and Panaceas. W. H. Freeman: New York, NY. 422 p.
Bunyard, B.A. & Justice, J. (2020). Amanitas of North America. The Fungi Press: Batavia, IL. 336 p.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Duffy, T.J. (2008). Toxic Fungi of Western North America. MykoWeb.
Geml, J., Laursen, G.A., K., O., Nusbaum, C. & Taylor, D.L. (2006). Beringian origins and cryptic speciation events in the fly agaric (Amanita muscaria). Molecular Ecology 15: 225-239.
Jenkins, D.T. (1977). A Taxonomic and Nomenclatural Study of the Genus Amanita and Section Amanita for North America. J. Cramer: Vaduz. 126 p.
Jenkins, D.T. (1986). Amanita of North America. Mad River Press: Eureka, CA. 197 p.
Jenkins, D.T. & Petersen, R.H. (1976). A neotype specimen for Amanita muscaria. Mycologia 68: 463-469.
Rubel, W. & Arora, D. (2008). A Study of Cultural Bias in Field Guide Determinations of Mushroom Edibility Using the Iconic Mushroom, Amanita muscaria, as an Example. Economic Botany 62(3).
(PDF)
Siegel, N. & Schwarz, C. (2016). Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p. (PDF)
Spoerke, D.G. & Rumack, B.H. (1994). Handbook of Mushroom Poisoning: Diagnosis and Treatment. CRC Press: Boca Raton, FL. 456 p.
Thiers, Harry D. (1982). The Agaricales (Gilled Fungi) of California. 1. Amanitaceae. Mad River Press: Eureka, CA. 53 p.
— yellow form
— very young
— very young
— A. muscaria & A. gemmata growing side-by-side
