The cap of young specimens of Agaricus mushrooms is sphere-shaped, then it’s semicircular and bulging, the cap’s edges are turned down and connected to the stipe with a loose tissue (the veil). As the mushroom develops, the cap’s edges melt and the tissue tears up and a soporiferous layer appears (hymenium). The cap’s surface’s color ranges from white to rich brown with many shades even on fruit bodies of the same mycelium. The cap’s surface could be smooth or scaly and it darkens when pressed on. The stipe is thick, smooth, and cylindrical with a slightly bulging base; it’s fleshy and sometimes hollow. The ring left from the tissue is wide and is set near the middle of the stipe. The gills are very frequent. New gills are pink in color and the spores develop, they become dark-brown with a purple shade. The flesh is white, thick and juicy; it becomes pink or red when broken. It has a strongly pronounced smell and a mushroom taste. In natural conditions a wild Agaricus Bisporus is not often seen. It usually grows in big bunches in dunged areas, gardens, on compost piles and in pastures.
Since the basic substrate for this mushroom is composted manure, better conditions are created for it when it’s cultivated artificially.
There are two kinds of Agaricus Bisporus: white and brown.
Agaricus Bisporus kind exists of four different groups of strains: «white strains», «off-white strains», «hybrid strains» – which are hybrids obtained from white and off-white strains, and «brown strains».
The white strains are characterized by white fruit bodies, smooth, often silky caps with no scales. The mushrooms are relatively small and their average weight is about 4-8 gr. Mostly, these mushrooms are cultivated to be sold fresh, so they are picked their caps closed.
The off-white strains, which are also called «intermediate» inherited the traits of the white and brown mushrooms. Their caps are white, but they’re much bigger in size, just like the brown strains (mushroom’s average weight is 8-12 gr.), it also has scales. The scales are often brown. They are high-yielding and easy to harvest mechanically and packing. But they have one shortcoming: The gills of fully developed mushrooms are dark-brown in color and because of this when packing, all other mushrooms darken and look unappealing.
The hybrid strains were obtained as the result of crossing white and off-white strains, their fruit bodies are of better quality and their yield is higher. Their cap is white and smooth like the one of the white strains, and their stipe is short like the one of the off-white strains.
These mushrooms can be sold fresh or be processed.
While working on creating new strains, breeders try to give the hybrids the best traits of their parents.
Brown strains are cultivated in small amounts today. The cap’s color ranges from dark-brown to light-brown, depending on the strain. The stipe stays white unlike the wild type of mushroom, the stipe of which is also brown. These mushrooms are cultivated to become rather big (the diameter of the cap is 12-15 cm), they are picked being fully developed and with an open cap, then delivered to the principal to made into special dishes.