The Genus Amanita

[ Basidiomycetes > Agaricales > Amanitaceae . . . ]

by Michael Kuo

The mushrooms in Amanita include some of the world's most famous (and most deadly) fungi. Amanita species are recognized by their (usually) pale gills, which are free from the stem; their white spore prints; the presence of a universal veil that often creates a volva or other distinctive features on the stem; and their more or less dry caps (as opposed to the slimy caps in Limacella). Many species of Amanita have warts or patches on their caps, and most have a ring on the stem.

Although there are some edible mushrooms in the genus, no amanita should be eaten. The genus contains lethal mushrooms that are quite similar to the "edible" ones. See Mushroom Toxins and The Meixner Test for information on the poisons present in the most dangerous amanitas--and see the comments labeled "Amanita Bravado," below.

Identification

In general, amanitas are not as hard to identify as many gilled mushrooms are, though there are difficult and frustrating areas within the genus--particularly among the white "Lepidellas." Plenty of good literature is available for the genus (see below), and identification is based on a set of fairly easily distinguished, reasonable characters ("reasonable" as opposed to the characters in Russula, for example, where subtle differences in taste or the "peelability" of the cap cuticle are operative). For an introduction to amanita identification, see the material below--and try out my Key to a Few Common and Disctinctive Amanitas.

Amanita identification begins with the base of the stem, which means that you will need to dig your specimens out of the ground with a pocket knife. Do this carefully, because some of the potentially important features are fragile and easily destroyed. The shape of the stem base is important. Is there a bulb, or does the stem taper gradually? If there is a bulb, is it dramatic, or less abruptly swollen? Does the stem "radicate," forming a root that extends into the ground? Also important is the disposition of the universal veil, which can vary substantially. Here are illustrations of some of the classic amanita stem bases:

"Amanita Bravado" is not a rare species of amanita; it's a behavioral disorder. Sometimes, mushroom hunters with considerable identification skills are able to successfully identify and eat some of the non-poisonous amanitas--like Amanita rubescens or Amanita novinupta--without experiencing ill effects. However, amanitas are poorly known in North America, and Amanita rubescens, for example, does not even occur on our continent, despite its inclusion in North American treatments (including this site). People who eat amanitas, in my humble opinion, are exercising poor judgment. But the real problem occurs when these people begin to brag about eating amanitas. In some mushroom clubs and mycological societies, experienced mushroomers love to engage in Amanita Bravado, and daring to eat amanitas can become almost a rite of passage for new and inexperienced club members. This is a dangerous state of affairs for obvious reasons, and the people involved have made little social progress since high school. If you have enjoyed a nice meal of amanitas, keep it to yourself. Bragging about it only creates social pressure for others, with less identification experience, to make a potentially fatal mistake.

References: Amanita Keys

Arora, D. (1986). Mushrooms demystified: A comprehensive guide to the fleshy fungi. Berkeley: Ten Speed Press. 959 pp.

Jenkins, D. T. (1986). Amanita of North America. Eureka, CA: Mad River Press. 198 pp.

Kauffman, C.H. (1918). The gilled mushrooms (Agaricaceae) of Michigan and the Great Lakes region, Volumes I and II. New York: Dover. 924 pp. (1971 Reprint.) This book is available online here.

Lindgren, J. (1998). Trial key to the species of Amanita in the Pacific Northwest. Retrieved from the Pacific Northwest Key Council Web site: http://www.svims.ca/council/Amanit.htm

Moser, M. (1983). Keys to Agarics and Boleti (Polyporales, Boletales, Agaricales, Russulales). Ed. Kibby, G. Transl. Plant, S. London: Roger Phillips. 535 pp.

Smith, A. H., Smith, H. V. & Weber, N. S. (1979). How to know the gilled mushrooms. Dubuque, Iowa: Wm. C. Brown. 334 pp.

Thiers, H. D. 1982. The Agaricales of California. 1. Amanitaceae. Eureka, CA: Mad River Press.

Tulloss, R. E. (2003). Amanita found in northeastern North America. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/nekey.pdf

Tulloss, R. E. (2003). Amanitaceae of Costa Rica. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/costaric.pdf

Tulloss, R. E. (2003). Amanita in the Pacific Coastal states of the U. S. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/pnwcakey.pdf

Tulloss, R. E. (2003). Key to rubescent taxa in Amanita section Validae. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/valirube.pdf

Tulloss, R. E. (2003). Provisional key to Amanita stirps Crocea, stirps Fulva, and stirps Romagnesiana. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/crocekey.pdf

Tulloss, R. E. (2003). Visual key to the sections of Amanita. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/secttree.pdf

Tulloss, R. E. (2004). Amanita section Phalloideae in the U. S. with membranous, limbate to saccate volvas. Retrieved from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/phallimb.html

Tulloss, R. (2007). Notes on Amanita section Caesareae, Torrendia, and Amarrendia (Agaricales, Amanitaceae) with provisional division into stirpes and world key to species of the section. Retrieved March 18, 2008 from the Studies in the genus Amanita Web site: http://pluto.njcc.com/~ret/amanita/key.dir/hemibkey.pdf

Further References

Ammirati, J. F., Thiers, H. D. & Horgan, P. A.. (1977). Amatoxin-containing mushrooms: Amanita ocreata and A. phalloides in California. Mycologia 69: 1095-1108.

Bas, C. (1969). Morphology and subdivision of Amanita and a monograph on its section Lepidella. Persoonia 5: 285-579.

Bas, C. (2003). A broader view on Amanita. Retrieved April 19, 2008 from the Gruppo Micologico 'G. Bresadola' Web site: http://www.mtsn.tn.it/bresadola/bgmb/bgmb_2000_2_bas.asp

Beardslee, H. C. (1914). Notes on a few Asheville fungi. Mycologia 6: 88-92.

Began, T. J. (1988). The genus Amanita in southern Illinois including cultural characters and a detailed study of volval anatomy in section Lepidella. MA Thesis, Southern Illinois University. Carbondale, IL. 127 pp.

Bruns, T. D. et al. (2002). Survival of Suillus pungens and Amanita francheti ectomycorrhizal genets was rare or absent after a stand-replacing wildfire. New Phytologist 155: 517-523.

Coker, W. C. (1917). The amanitas of the eastern United States. Journal of the Elisha Mitchell Scientific Society 33: 1-88.

Drehmel, D., Moncalvo, J. & Vilgalys, R. (1999). Molecular phylogeny of Amanita based on large-subunit ribosomal DNA sequences: implications for taxonomy and character evolution. Mycologia 91: 610-618.

Guzman, G. (1981). Distribution of Amanita nauseosa. Mycotaxon 12: 522-524.

Hallen, H.E., H. Luo, J. S. Scott-Craig & J. D. Walton (2007). Gene family encoding the major toxins of lethal Amanita mushrooms. Proceedings of the National Academy of Science 104: 19097-19101.

Jenkins, D. T. (1978). A study of Amanita types I. Taxa described by C. H. Peck. Mycotaxon 7: 23-44.

Jenkins, D. T. (1978). A study of Amanita types II. A. ocreata Peck. Mycotaxon 7: 371-372.

Jenkins, D. T. (1979). A study of Amanita types III. Taxa described by W. A. Murrill. Mycotaxon 10: 175-200.

Jenkins, D. T. & Vinopal, J. (1979). A new Amanita from Florida. Mycotaxon 8: 177-180.

Jenkins, D. T. (1979). A new species of Amanita. Mycotaxon 8: 174-176.

Jenkins, D. T. (1980). A new species of Amanita. Mycotaxon 10: 296-298.

Jenkins, D. T. (1981). A new species of Amanita. Mycotaxon 13: 112-114.

Jenkins, D. T. (1982). A new species of Amanita. Mycotaxon 14: 233-236.

Jenkins, D. T. (1983). A new species of Amanita. Mycotaxon 16: 414-416.

Jenkins, D. T. (1984). A new species of Amanita IV. Mycotaxon 20: 315-317.

Jenkins, D. T. (1985). A new species of Amanita VII. Mycotaxon 24: 283-286.

Jenkins, D. T. (1988). A new species of Amanita from North America: Amanita levistriata. Mycotaxon 32: 415-419.

Largent, D. L., N. Sugihara & A. Brinitzer (1980). Amanita gemmata, a non-host-specific mycorrhizal fungus of Arctostaphylos manzanita. Mycologia 72: 435-439.

Miller, O. K.. Jr., Trueblood, E. & Jenkins, D. T. (1990). Three new species of Amanita from southwestern Idaho and southeastern Oregon. Mycologia 82: 120-128.

Moncalvo, J. M., Drehmel, D. & Vilgalys, R. (2000). Variations in modes and rates of evolution in nuclear and mitochondrial ribosomal DNA in the mushroom genus Amanita (Agaricales, Basidiomycota): Phylogenetic implications. Molecular Phylogenetics and Evolution 16: 48-63.

Morales-Torres, E. et al. (1999). Revision of Amanita alexandri and its similarity to Amanita polypyramis. Mycotaxon 73: 477-491.

Murrill, W. A. (1913). The amanitas of eastern North America. Mycologia 5: 72-86.

Oda, T., Tanaka, C. & Tsuda, M. Molecular phylogeny and biogeography of the widely distributed Amanita species, A. muscaria and A. pantherina. Mycological Research 108: 885-896.

Redecker, D. et al. (2001). Small genets of Lactarius xanthogalactus, Russula cremoricolor, and Amanita franchetii in late-stage ectomycorrhizal successions. Molecular Ecology 10: 1025-1034.

Stewart, H. L. & Grund, D. W. (1974). Nova Scotian fungi. New species and records of amanitas for the province. Canadian Journal of Botany 52: 331-379.

Thiers, H. D. & Ammirati, J. F. (1982). New species of Amanita from western North America. Mycotaxon 15: 155-166.

Tulloss, R. E. & Jenkins, D. T. (1986). Notes on distribution of Amanita albocreata. Mycotaxon 26: 81-83.

Tulloss, R. E. (1988). Amanita sinicoflava--a new species from eastern North America. Mycotaxon 32: 421-431.

Tulloss, R. E. (1989). Amanita eburnea--a new species from Central America. Mycotaxon 36: 1-7.

Tulloss, R. E. (1989). Amanita ristichii: A new species from New England with basidia dominantly 2-spored. Mycotaxon 35: 363-369.

Tulloss, R. E. & Wright, G. (1989). Amanita protecta--a new species from coastal southern California. Mycotaxon 34: 615-622.

Tulloss, R. E. (1990). Amanita crenulata--history, taxonomy, distribution, and poisonings. Mycotaxon 39: 393-405.

Tulloss, R. E. (1990). Amanita salmonescens--a new species from the southeastern United States. Mycotaxon 38: 125-132.

Tulloss, R. E. (1991). Amanita morrisii--history, taxonomy, and distribution. Mycotaxon 40: 281-286.

Tulloss, R. E. & Lindgren, J. E. (1992). Amanita smithiana--taxonomy, distribution, and poisonings. Mycotaxon 45: 373-387.

Tulloss, R. E., Ovrebo, C. E. & Halling, R. E. (1992). Studies on Amanita (Amanitaceae) from Andean Colombia. Memoirs of the New York Botanical Garden 66: 1-46.

Tulloss, R. E. (1993). Amanita pachysperma, Amanita subvirginiana, and Amanita virginiana (taxonomy and distribution) with notes on description of the lamella trama in Amanita. Mycotaxon 49: 449-475.

Tulloss, R. E. (1994). Type studies in Amanita section Vaginatae I: Some taxa described in this century (studies 1-23) with notes on description of spores and refractive hyphae in Amanita. Mycotaxon 52: 305-396.

Tulloss, R. E. & Lindgren, J. E. (1994). Amanita novinupta--a rubescent, white species from the western United States and southwestern Canada. Mycotaxon 51: 179-190.

Tulloss, R. E. & Lewis, D. P. (1994). Amanita westii--taxonomy and distribution. A rare species from the states bordering the Gulf of Mexico. Mycotaxon 50: 131-138.

Tulloss, R. E. (1995). Amanita longitibiale--A new species of Amanita section Phalloideae from central Mexico and southeastern U.S.A. Mycotaxon 54: 195-202.

Tulloss, R. E. & Moses, E. (1995). Amanita populiphila--a new species from the central United States. Mycotaxon 53: 455-466.

Tulloss, R. E. et al. (1995). Studies on Amanita (Amanitaceae) in West Virginia and adjacent areas of the mid-Appalachians. Preliminary results. Mycotaxon 56: 243-293.

Tulloss, R. E. (2000). Nomenclatural changes in Amanita. Mycotaxon 75: 329-332.

Tulloss, R. E. & Lindgren, J. E. (2005). Amanita aprica--a new toxic species from western North America. Mycotaxon 91: 193-205.

Weiss, M., Yang, Z-L. & Oberwinkler, F. (1998). Molecular phylogenetic studies in the genus Amanita. Canadian Journal of Botany 76: 1170- 1179.

Cite this page as:

Kuo, M. (2005, March). The genus Amanita. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita.html

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