Agaricus campestris - Field Mushroom

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

The Field Mushroom, Agaricus campestris, is the most commonly eaten wild mushroom in the British Isles. Meadows grazed by sheep, cattle or horses often produce vast quantities of these fungi of summer and early autumn.

It is not wise to take cap colour as a significant feature when identifying these kinds of mushrooms. Some Field Mushrooms are smooth and almost pure white while others are quite rough with dark-brown cap scales.

Identification guide

	Cap 3 to 10cm in diameter, the cap is creamy white, sometimes developing small scales as it matures. Usually the margin remains down-turned or slightly in-rolled even when the cap has expanded fully. The thick flesh is white, sometimes turning slightly pink when cut but never staining yellow.
	Gills Deep pink at first, the free crowded gills turn dark brown and eventually almost black as the fruitbody matures. Old specimens may become infested by maggots, which enter the cap flesh via the gills. Careful inspection is necessary, and it is inadvisable to include very old specimens in collections intended for food.
	Stem 3 to 10cm tall and 1 to 2cm in diameter, the white stem is smooth above the single, delicate ring and somewhat scaly below. It is more or less parallel and does not turn yellow when cut. The ring itself is ephemeral, and by the time the fruitbody is fully developed there is rarely much evidence of a ring remaining.
Spore print	Deep chocolate brown.
Odour/taste	Not distinctive.
Habitat	On soil among grass in pastures, playing fields and parks.
Season	June to October.
Occurrence	Frequent
Similar species	Agaricus bitorquis, the Pavement Mushroom, is very similar but with a thin double ring; it favours dry places beside paths. Agaricus arvensis, the Horse Mushroom, is usually somewhat larger that the Field Mushroom and, while having a similar whitish cap when you, at maturity it takes on a yellowish hue.