An edible fungus (Agaricus campestris), having a white
   stalk which bears a convex or oven flattish expanded portion called the
   pileus. This is whitish and silky or somewhat scaly above, and bears on
   the under side radiating gills which are at first flesh-colored, but
   gradually become brown. The plant grows in rich pastures and is
   proverbial for rapidity of growth and shortness of duration. It has a
   pleasant smell, and is largely used as food. It is also cultivated from
   spawn.