Toxic Fungi of Western North America

by Thomas J. Duffy, MD

Ethnicity and amanitin poisoning

Gordon Wasson, who researched the various cultural uses of mushrooms, divided societies into “mycophobic” and “mycophilic” (fearing and loving mushrooms). He considered the mycophobic cultures to include the Scandinavian countries, Great Britain, Canada and the United States. Countries considered mycophilic included France, Austria, Italy, Switzerland and the Slavic countries. In those countries, photographs and descriptions of both toxic and edible fungi often decorate the walls of primary schoolrooms.

Americans of Italian descent have had more than their share of Amanita phalloides poisoning, because of their like for "coccoli" or "coccora". Italian-American pickers may mistake Amanita phalloides for the edible "coccoli"--yellow or orange-yellow mushrooms described by Atkinson and Ballen as Amanita calyptroderma. The correct name under current ICBN rules is Amanita lanei (Murrill) Sacc.& Trott., but this name under Murrill’s concept refers to only the orangish fall species. (25) The similar pale yellow mushrooms found in the spring are probably a separate and unnamed species; these are also eaten as “coccoli”.

Amanita phalloides looks vaguely similar to the orange, often grayish, Amanita lanei, although the latter's thick membranous volva, often fish-like odor, thick single white membranous patch on the cap and striations at the cap border should suffice to distinguish them. Amanita phalloides has multiple thin patches of universal veil on the cap or sometimes none at all, should its fragile tissue completely weather away; the thin volva often collapses on the stipe. The thick “poison cup” is more evident in the case of the edible Amanita lanei. Amanita phalloides is not easily mistaken for the pale yellow spring form even if still fruiting, provided immature specimens are not collected. The “eggs” or young buttons are often collected but the difference from phalloides buttons is easily missed, even when cross-sectioned. Avoid the buttons entirely.

The greenish-yellow Amanita phalloides, often a dingy color, may approximate that of Amanita lanei quite well in poor light. At least one very experienced California pot-hunter picked one Amanita phalloides along with many Amanita lanei as darkness descended and greed gained the upper hand. A few mushrooms were eaten that night; the uneaten Amanita phalloides was found the next day. The rest of the collection was thrown out in horror.

The popularity of this mushroom is based on the orange Amanita caesarea of Mediterranean Europe, a species not found in the U.S., although a similar one may be found from Quebec to Texas (Amanita jacksonii) and another one in the Southern Rocky Mountains. Another species, Amanita colchiseiana (Tulloss nom. prov.), is found in the Chiricahua Mountains of Arizona. The Mexican species often called “caesarea” has been named Amanita basiana by Dr. Guzmán and Rodríquez-Guillén.

Americans of Asian extraction are poisoned more frequently than the general population because the amanitas involved resemble edible Asian species—the often off-white Amanita princeps and Amanita chepangiana. Both species tend to have a little yellow or yellowish brown, sometimes with a faint olive tinge—confined largely to the central area of the cap. Otherwise the pileus is white and it may be entirely so. Dr. Desjardin notes that both species are sold in markets, especially in Laos and Thailand, and that they tend to look somewhat like Amanita phalloides when the central area is colored yellowish brown.

Americans of Mexican extraction are also more likely to be poisoned than the general population by Amanita phalloides, since the amatoxic taxons in Mexico are typically white with the exception of the greyish Amanita arocheae Tulloss, Ovrebo and Halling. Amanita phalloides with its brassy green cap is not found or is exceedingly rare in Mexico. The problem is that amanitas are traditionally a substantial part of the mushroom diet in some areas of Mexico as well as Hebeloma, Lyophyllum and Melanoleuca—fungi, which are all very low on the list of US pot-hunters. Indigenous peoples in Mexico identify them by local tradition, habitat and over-all appearance. Four deaths from Amanita phalloides in San Diego were caused by a delay to hospital admission, because the men were fearful of their illegal immigrant status. The San Francisco Chronicle noted January 6, 2007 (page 1, section B) that six members of a family were seriously poisoned by Amanita phalloides because the grandmother, used to foraging in Mexico, failed to identify the Amanita phalloides picked.

A number of white amanitas as well as others are eaten in Mexico. The edible Amanita tuza, for example, has a very thick ±cottony volva similar to our Amanita lanei (calyptrata) and is equally popular. This edible taxon would not seem likely to be confused with Amanita magnivelaris or the other amatoxic fungi noted above, but occasionally misidentifications occur. Amanita tuza not only has a very thick volva, but it has marked, slightly raised striations at the edge of the cap, which are lacking in Amanita magnivelaris and the other toxic taxa. Amanita tuza grows just below the surface of the ground initially and forms mounds resembling those of gophers (thus its species epithet). Other edible white species with a thick volva are close to the Mexican version of the edible (but orange) "Caesar's mushroom" and include Amanita basii Guzmán & Rodríquez-Guillén as well as Amanita laurae and Amanita yema of the same authors. (13a) With this abundance of edible amanitas in Mexico, latino immigrants to California continue to be in particular danger of poisoning by Amanita phalloides and Amanita ocreata.

In central Mexico, some folk beliefs are 1. Cook mushrooms with a garlic clove. If the garlic turns blue or black, the mushrooms are poisonous; 2. Do not eat mushrooms which grow on dung; 3. Do not eat mushrooms if the flesh turns a different color when cut; 4. Do not eat mushrooms with an unpleasant odor. (31) It is not surprising that large poisonings occasionally occur, such as the 16 or so people poisoned by white amanitas in 2005 and reported in the Spring issue of the 2007 McIlvainea. Eight of these Chiapas victims died.