Agaricus vaporarius

A notable group of poisonous Agaricus is the clade around the yellow-staining mushroom, A. xanthodermus. One species reported from Africa, A. aurantioviolaceus, is reportedly deadly poisonous. Far more dangerous is the fact that Agaricus, when still young and most valuable for eating, are easily confused with several deadly species of Amanita (in particular the species collectively called "destroying angels", as well as the white form of the appropriately-named "death cap" Amanita phalloides), as well as some other highly poisonous fungi. An easy way to recognize Amanita is the gills, which remain whitish at all times in that genus. In Agaricus, by contrast, the gills are only initially white, turning dull pink as they mature, and eventually the typical chocolate-brown as the spores are released. Even so, Agaricus should generally be avoided by inexperienced collectors, since other harmful species are not as easily recognized, and clearly recognizable mature Agaricus are often too soft and maggot-infested for eating. When collecting Agaricus for food, it is important to identify every individual specimen with certainty, since eating just one Amanita mushroom cap can cause serious illness. Reacting to some distributors marketing dried agaricus or agaricus extract to cancer patients, it has been identified by the U.S. Food and Drug Administration as a "fake cancer 'cure'". The species most often sold as such quack cures is A. subrufescens, which is often referred to by the erroneous name "Agaricus Blazei" and advertised by fanciful trade names such as "God's mushroom" or "mushroom of life", but can cause allergic reactions and even liver damage if consumed in excessive amounts.