The botanical name of mushroom that belongs to this kind is Agaricus bisporus. The cap of the mushroom is 2.5-14 cm in diameter. The shape of the cap is convex and seems to be round at first sight. The structure is nearly flat or broadly convex. The cap has pressed-down fibers as well as certain small scales. Some cultivated varieties of Agaricus bisporus have a white-colored cap while there are some others where the color of the cap is brown. In other varieties, there is a reddish to pinkish tint in the mushroom when it is properly rubbed. The gills are produced free from the stem and are short in size. The color of the gills is pink at first but turns dark brown or black with time. The stem of the mushroom is 2-7cm long and 1-2.5 cm thick.