Mushrooms

Some species of mycorrhizal fungi develop mushrooms that are deadly poisonous. Perhaps the most famous, and most-rapidly killing species in this respect are the death or destroying angel (Amanita virosa) and the deathcap (A. palloides). There are other species of deadly mushrooms in the genus Amanita, and in the genera Chlorophyllum (green gill), Cortinarius (webcaps), Galerina (autumn skullcaps), Gyromitra (false morels), and Lepiota (parasol mushrooms). However, these are not, by any means, the only poisonous mushrooms that may be commonly encountered in wild habitats in North America. There are numerous other species of deadly mushrooms, which are never to be eaten.

A number of fungi are used as drugs, to induce hallucinations, feelings of well-being, and other pleasurable mental states. The fly agaric (Amanita muscaria) is a widespread species of Eurasia, North America, and Central America, and is a well-known poisonous mushroom. However, in smaller doses this species can induce pleasant intoxication and hallucinations, and it has long been used by many cultures to induce these effects. This has been the case in Siberia, elsewhere in northeastern Asia, Central Asia, and India, where the drug is known by the indigenous name "soma." The fly agaric has also been used in northwestern Europe, where Viking warriors sometimes consumed this drug prior to battle and certain ceremonies, and were known as "berserkers," and in Central America, where the fungus was considered to be a food from the gods. In the famous children's story, Alice in Wonderland, Alice could change her size from very small to very large, by nibbling on a mushroom. This tale was undoubtedly influenced by the author's knowledge of the hallucinogenic properties of Amanita muscaria. It is well-known that prolonged or frequent use of this hallucinogen is damaging to the nervous system, and that large doses can be lethal, but this mushroom has nevertheless been important in many cultures, and is still routinely used for certain types of ceremonies.

Various species of American mushrooms known as psilocybin (Psilocybe spp.) are also hallucinogenic. These were used in religious ceremonies by some Amerindian cultures, for example, the Aztecs, who knew these mushrooms as teonanacatyl (especially using P. mexicana). However, these mushrooms are mostly used today as recreational drugs. Other mushroom-producing fungi that contain the same active ingredient, known as psilocybin, are species in the genera Conocybe, Paneolus, Psathyrella, and Stropharia.

A therapeutic drug is manufactured from the fruiting bodies of the ergot (Claviceps purpurea), which is a parasite on the flowering heads of certain grasses, especially rye (Secale cereale). The ergot fungus attacks the young fruits of the grasses, and then develops a bulbous, purplish structure. These are collected and used to make a medicine useful in treating low blood pressure, hemorrhages, and other maladies.