Agaricus

Agaricus is a genus of fungi in the family Agaricaceae, comprising several hundred species of gilled mushrooms. It includes some of the most widely cultivated and consumed mushrooms, notably Agaricus bisporus, which, in its immature form, is sold as the white button mushroom and matures into cremini or portobello varieties.

Members typically have a cap with a smooth to scaly surface that ranges in color from white to brown, a stout stalk often bearing a ring—the remnant of a partial veil—and gills on the cap underside that are initially pale and become brown as spores mature. They produce a brown spore print. Many species have a pleasant, mushroomy odor; some bruise or color changes occur in certain species, and a few (such as A. xanthodermus) stain yellow when damaged.

Agaricus species are typically saprotrophic, growing on rich soils, leaf litter, dung, or decaying wood, and are common in grassy places, woodland edges, and compost piles across temperate regions.

The genus is cosmopolitan and diverse, with species that range from edible to inedible or mildly toxic, so correct identification is important.

Among edible forms, A. bisporus is the primary cultivated species worldwide, with varieties sold as button, cremini, or portobello mushrooms. Other edible species include A. campestris (meadow mushroom) and A. subrufescens (almond or Brazilian mushroom). Some agarics can provoke adverse reactions in susceptible individuals.