A mushroom is the fleshy, spore-bearing
fruiting body of a fungus, typically produced
above ground on soil or on its food source.
The standard for the name "mushroom" is
the cultivated white button mushroom,
Agaricus bisporus; hence the word "mushroom"
is most often applied to those fungi
(Basidiomycota, Agaricomycetes) that have a
stem (stipe), a cap (pileus), and gills (lamellae, sing. lamella)
or pores on the underside of the cap.
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