Agaricus bisporus

Agaricus bisporus known variously when white as common mushroom, button mushroom, white mushroom, cultivated mushroom, table mushroom, champignon mushroom,
when brown as Swiss brown mushroom, Roman brown mushroom, Italian brown, Italian mushroom, cremini/crimini mushroom, brown cap mushrooms, chestnut mushroom, and when mature as Portobello mushroom is an edible basidiomycete mushroom native to grasslands in Europe and North America.

Agaricus bisporus is cultivated in more than 70 countries and is one of the most commonly and widely consumed mushrooms in the world.

The common mushroom has a complicated taxonomic history.
It was first described by English botanist Mordecai Cubitt Cooke in his 1871 Handbook of British Fungi, as a variety (var. hortensis) of Agaricus campestris. Danish mycologist Jakob Emanuel Lange later reviewed a cultivar specimen, and dubbed it Psalliota hortensis var. bispora in 1926.

In 1938, it was promoted to species status and renamed Psalliota bispora.
Emil Imbach imparted the species' current scientific name, Agaricus bisporus, after the genus Psalliota was renamed to Agaricus in 1946. The specific epithet bispora distinguishes the two-spored basidia from four-spored varieties.