Mycology Wiki
Agaricus bisporus

Agaricus bisporus

  • Portobello
  • White button
  • Crimini
  • Champignon
  • Agaricus brunnescens
  • Agaricus hortensis
Scientific Classification
Kindom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Agaricaceae
Genus: Agaricus
Species: Bisporus

Agaricus bisporus, commonly known as the Portobello, Button or Crimini mushroom, is the most widely cultivated mushroom in the world. The mushroom grows naturally in grasslands, fields and meadows in North America and Europe.

  • Cap: 3-16 cm, convex to broadly convex or nearly flat in age; dry; smooth or with pressed-down fibers or small scales; white in some varieties, brown in others.
  • Spore print: brown
  • Spores: 5.5-8.5 x 4-6.5 µ; elliptical; smooth. Basidia 2-spored.
  • Bruising: brownish
  • Gills: free from the stem; close; pinkish to pinkish brown at first, becoming dark brown to blackish.
  • Stipe: 2-8 cm long; 1-3 cm. thick; sturdy; more or less equal; smooth or with small scales below the ring; white, often bruising brownish; with a ring that sometimes disappears in maturity.
  • Veil: absent
  • Mycelium: whitish, longitudinally radical, soon becoming cottony, and in age forming a thick, tenacious mycelial mat. Aged mycelium often secretes yellowish to orangish droplets of a metabolite which is a toxin to nematodes.)


Agaricus bisporus is the most widely cultivated edible mushroom in the world.


Spawn run

Primordia Formation

Fruit body Development


Since bisporus a dung-loving species, it will grow exceptionally well on horse and cow manure.



Carcinogenic Properties[]

Paul Staments has performed analysis of several Agaracis mushroom species and found that the fruit bodies tend to contain agaratine, a known carcinogen[1].

The bottom line is that I do not ingest products made from Agaricus fruitbodies unless they have been heated over 415˚ F, such as when mushrooms are broiled on a pizza. If the Agaricus industry would conduct a clinical study of their member farms and their employees, and compare their cancer rates relative to baseline populations, the looming questions as to whether Agaricus ingestion has net negative or positive effects could be put to rest. I think this responsibility is incumbent upon the Agaricus industry to finance and spearhead this study using unbiased, third party medical epidemiologists.

Natural Habitat[]

Bisporus is a coprophilic fungus (a dung-loving species) that often colonizes the dung of large herbivores, most notably cows and other grazing mammals such as goats. The mushroom grows naturally in grasslands, fields and meadows in North America and Europe. You can find it in late June through early fall

See Also[]

  1. {Cite web|url= and The Himematsutake Mushroom, Agaricus brasiliensis (aka Agaricus blazei)|accessdate=2006-11-26|publisher=FungiPerfecti|year=2008|author=Staments|format=html}}