We’re kicking off a new educational endeavor featuring a new mushroom each month and the first species we’re exploring is Agaricus campestris!

Agaricus campestris is a gilled mushroom that is commonly known as the field or meadow mushroom. It is closely related to the common white button mushroom that can be found in grocery stores, and is also edible, having a similar, mild taste, but one that is richer and nuttier. The common name, field mushroom, denotes the grassy, soil based habitat that Agaricus campestris can be found in all over the world after it rains, as either a solitary mushroom, or in small clusters or circles (known as fairy rings).

The genus name, Agaricus, comes from the Ancient Greek word “agarikon” meaning “tree fungus.” The species name, campestris, comes from the Latin word for field or plain.

The cap of Agaricus campestris is white, and on average measures about 2 to 5 inches in diameter. The stipe, or stem, is also white, and has a thin ring around it.

CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1710232

The gills on the hymenium (underside of the cap) first have a pink color, but over time this becomes brown.

If you’re going to forage and eat this mushroom, be careful not to confuse it with Agaricus xanthodermus or Agaricus californicus, which both look similar, but are poisonous and will make you sick

Agaricus campestris is a saprobic (or saprophytic) mushroom. This means that the mushroom acts as a decomposer, and breaks down dead, organic material in order to make energy and grow biomass. Saprobic mushrooms also generate carbon dioxide and organic acids. Organic acids are essential to ecosystem health, because they may contribute to many important functions in soil, including metal detoxification (removal of toxic heavy metals from soil), mineral weathering (breakdown of rocks and minerals, allowing for uptake by other plants), and plant root nutrient acquisition.

Agaricus campestris has been used in traditional medicine to treat diabetes. A 1998 study in the UK administered an extract of field mushrooms to mice, and observed its effects on glucose and insulin. The mushroom extract had a stimulatory effect on insulin secretion of the mice.

Field mushrooms are also a healthy addition to your diet, because they contain several essential nutrients. Per 100g of Agaricus campestris consumed, there will be:

0.52mg (~50% daily recommended amount) of riboflavin (vitamin B2), which helps the body convert carbohydrates into usable energy in the form of glucose
8.6 mg (~10% daily recommended amount) of ascorbic acid (vitamin C), which supports immune function
5.85 mg (~40% daily recommended amount) of niacin (vitamin B3), which helps convert nutrients into energy, and also create and repair DNA

References:

Davis, R. Michael; Sommer, Robert; Menge, John A. (2012). Field Guide to Mushrooms of Western North America. Berkeley: University of California Press. pp. 224–225. ISBN 978-0-520-95360-4. OCLC 797915861.

Michael Kuo. Agaricus campestris. MushroomExpert.com. https://www.mushroomexpert.com/agaricus_campestris.html

“Agaricus campestris: Meadow Mushroom Identification and Benefits.” Healing Mushrooms. https://healing-mushrooms.net/agaricus-campestris

“Fungi.” SUNY Cortland. https://cortland.edu/waldbauer-trail/14-fungi.html

“Agaricus campestris.” Urban Mushrooms. https://urbanmushrooms.com/index.php?id=13

“Agaricus campestris: The Ultimate Mushroom Guide.” Ultimate Mushroom. https://ultimate-mushroom.com/edible/25-agaricus-campestris.html

Ingham, Elaine R. “Soil Fungi.” NRCS Soils USDA. https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053864

Jones et al, 2003. “Organic acid behavior in soils – misconceptions and knowledge gaps.” Plant and Soil. https://doi.org/10.1023/A:1022304332313

Gray, A., & Flatt, P. (1998). Insulin-releasing and insulin-like activity of Agaricus campestris (mushroom), Journal of Endocrinology, 157(2), 259-266. Retrieved Aug 3, 2022, from https://joe.bioscientifica.com/view/journals/joe/157/2/259.xml

Anderson, E. E., and Carl Raymond Fellers. "The food value of mushrooms (Agaricus campestris)." Proceedings. American Society for Horticultural Science. Vol. 41. 1942.

Image Sources:

Image 1: https://www.mushroomexpert.com/images/contrib/bulliard_agaricus_campestris_01.jpg

Attribution to Biodiversity Heritage Library and New York Botanical Garden

Image 2: https://en.wikipedia.org/wiki/Fairy_ring#/media/File:Fairy_ring_on_a_suburban_lawn_100_1851.jpg

Public domain

Image 3: https://en.wikipedia.org/wiki/Agaricus_campestris#/media/File:Agaricus_campestris.jpg

Attribution to Nathan Wilson

Image 4: https://www.wildfooduk.com/wp-content/uploads/2018/01/Field-10.jpg

Attribution to WildFoodUK