Field Mushroom

Agaricus campestris

Agaricus campestris is commonly known as the Field Mushroom. It is a familiar and widely distributed grassland saprotroph, growing after rain on rich meadowland, pasture and lawns, especially in late summer and autumn. It is found in large numbers on rich grassland just below the soil surface where it rots dead organic material. The cap is smooth and pure white in young specimens, and flattens with maturity. Gills are free from the stipe and are pale pink in young specimens but darken to a rich chocolate brown as spores mature. It has a short-lived partial veil and the pale stipe is often cylindrical, leaving a faint ring on the stipe. [1][2]

A. campestris is an important saprotrophic member of open grassland ecosystems. It is a grazer of dead organic matter, including dead roots, grass litter and manure residues. Its recycling of dead organic matter into soil carbon and nitrogen, improves and maintains the nutrient cycling, microbial biodiversity, and vigour of higher plants in meadow ecosystems. It is often seen in nutrient-rich meadows which have not been too overgrazed and may be considered an indicator species of soil moisture, nutrient levels and overall equilibrium in those systems. [2][3][4]

It has long been claimed as the wild progenitor of the commercial button mushroom, but should not be confused with white Amanitas, some of which are deadly poisonous and also often found on grasslands. [5] In its natural grassland habitat it remains a keystone species of decomposers. [6]

[1] Kuo, Michael.“Agaricus campestris.” MushroomExpert.com. https://mushroomexpert.com/agaricus_campestris.html

[2] RedList.info.“Agaricus campestris – A decomposer fungus, widespread in pastures and other grasslands after rain from late summer onwards, worldwide.” RedList.info. https://redlist.info/iucn/species_view/356498

[3] Plantiary.“Meadow Mushroom (Agaricus campestris) – Identification, Habitat & Uses.” Plantiary Species Database. https://plantiary.com/mushroom/agaricus-campestris_190.html

[4] Kubicek, Christian P., & Irina S. Druzhinina (eds.).“Nutrient Cycling by Saprotrophic Fungi in Terrestrial Habitats.” In Environmental and Microbial Relationships. The Mycota Vol. 4, pp. 287-300. Springer, 2007. https://doi.org/10.1007/978-3-540-71840-6_16

[5] MykoWeb.“Agaricus campestris – FAQ and confusion with toxic species.” MykoWeb – California Fungi. https://www.mykoweb.com/CAF/species/Agaricus_campestris.html

[6] Mushrooms of Connecticut Website.“Field Mushroom, Meadow Mushroom – Agaricus campestris.” https://mushroomsofct.com/mushroom-index/agaricus-campestris/