Cultivated white mushrooms from the supermarket

The white mushroom (Agaricus bisporus), also called the common mushroom, cultivated mushroom, and called champignon de Paris in France, is the most widely cultivated mushroom in the world. Virtually every grocery store in the western world carries this mushroom (in canned and fresh preparations). An agaric, its gills are often left on in preparations. It can be found cooked on pizzas and casseroles, raw on salads, and in various forms in a variety of dishes.

Portobello mushroom is a marketing name for a large brown strain of the same fungus. Portobellos are left to mature and take on a toadstool-shaped appearance before picking. During maturation, their color darkens and their flavor changes.

A familiar wild mushroom, the meadow mushroom , can be found throughout much of the United States. However, care must be taken, as it resembles the immature stage of a number of deadly poisonous Amanita species.

Growers of white mushrooms often must watch out for the red-capped weed Panaeolus (Panaeolus subbalteatus), a hallucinogenic mushroom that grows in the same environment. Panaeolus subbalteatus is found on manure and rotting hay in the wild, and is frequently found in the compost used by white mushroom cultivators. With its differently shaped reddish-brown cap, it does not look similar to the white mushroom, which greatly eases finding and removing it from the crop.