Mushroom, the conspicuous umbrella-shaped fruiting body sporophore of certain fungi, typically of the order Agaricales in the phylum Basidiomycota but also of some other groups. Popularly, the term mushroom is used to identify the edible sporophores the term toadstool is often reserved for inedible or poisonous sporophores. There is, however, no scientific distinction between the two names, and either can be properly applied to any fleshy fungus fruiting structure. In a very restricted sense, mushroom indicates the common edible fungus of fields and meadows Agaricus campestris. A very closely related species, A. bisporus, is the mushroom grown commercially and seen in markets...