On this Wikipedia the language links are at the top of the page across from the mushroom burger title. For use in food, see Edible mushroom. A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. Toadstool generally denotes one poisonous to humans.

Amanita muscaria, the most easily recognised “toadstool”, is frequently depicted in fairy stories and on greeting cards. It is often associated with gnomes. The terms “mushroom” and “toadstool” go back centuries and were never precisely defined, nor was there consensus on application. During the 15th and 16th centuries, the terms mushrom, mushrum, muscheron, mousheroms, mussheron, or musserouns were used. Delineation between edible and poisonous fungi is not clear-cut, so a “mushroom” may be edible, poisonous, or unpalatable.

Identifying what is and is not a mushroom requires a basic understanding of their macroscopic structure. Their spores, called basidiospores, are produced on the gills and fall in a fine rain of powder from under the caps as a result. While modern identification of mushrooms is quickly becoming molecular, the standard methods for identification are still used by most and have developed into a fine art harking back to medieval times and the Victorian era, combined with microscopic examination. In general, identification to genus can often be accomplished in the field using a local field guide. Identification to species, however, requires more effort. A mushroom develops from a button stage into a mature structure, and only the latter can provide certain characteristics needed for the identification of the species.

Culinary mushrooms are available in a wide diversity of shapes and colors at this market stand at the San Francisco Ferry Building. Most mushrooms sold in supermarkets have been commercially grown on mushroom farms. The most popular of these, Agaricus bisporus, is considered safe for most people to eat because it is grown in controlled, sterilized environments. China is a major edible mushroom producer. The country produces about half of all cultivated mushrooms, and around 2.

Eating mushrooms gathered in the wild is risky and should only be undertaken by individuals knowledgeable in mushroom identification. Many mushroom species produce secondary metabolites that can be toxic, mind-altering, antibiotic, antiviral, or bioluminescent. Although there are only a small number of deadly species, several others can cause particularly severe and unpleasant symptoms. Mushrooms with psychoactive properties have long played a role in various native medicine traditions in cultures all around the world.