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Agaricus arvensis   (Horse Mushroom)
North America, Europe
Cap 8-20 cm diameter, stem 8-10 cm tall * 2-3 cm diameter

Agaricus arvensis, commonly known as the horse mushroom, is a sometimes massive agaric that has a white cap, ringed stem, and pink or chocolate colored gills. It grows on soil (often heavily fertilized) or on vegetable debris.

Cap white or cream colored, may have fine scales, first hemispherical in shape before flattening out with maturity. Flesh is white, firm and thick. Gills are at first white, becoming pink, then chocolate brown or blackish, free and crowded. Stem is white or cream; it is slightly club-shaped and smooth or finely scaly below the ring. Ring is white or cream, pendulous and superior. Viewed from below, on a closed-cap specimen, it has a well-developed 'cogwheel' pattern around the stem.

Similar species There are several similar species. Agaricus macrosporus are very fleshy, with scaly stem girdles. Agaricus sylvicola is a woodland variety. Agaricus augustus and Agaricus xanthoderma are also similar. Be careful not to confuse it with the deadly poisonous Amanita virosa, which has white gills.

Agaricus arvensis on the web site.

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If you plan to collect fungi to be eaten, misidentified mushrooms can make you sick or kill you. Do not eat mushrooms you are not 100% certain of. Use many resources, and be skeptical of your own conclusions. The site takes no responsibility for damage caused by wrong identifications. If you continue, you agree to view this website under these terms.