Agaricus sylvaticus

Cap	Agaricus silvaticus has a cap diameter of 7 to 15 cm. Domed at first, the scaly cap expands until it is almost flat. Beneath the surface, which is light russet-brown and covered with reddish-brown scales that are more dense towards the middle of the cap, the flesh is white. Upon cutting the thin, firm cap flesh it turns red and eventually brown.
Gills	Initially pink, the free, crowded gills turn redder and then dark brown as the spores mature.
Stipe	The stem, which is 1 to 1.2 cm in diameter, is more or less parallel sided above a slightly bulbous base. When cut, the solid stem flesh turns red and eventually brown. Above the large, floppy single ring the stem is smooth, while below the ring it is finely scaly.
Spore print	Chocolate brown.
Odour/taste	Not distinctive.
Habitat	Often in groups in mixed woodland and under trees in parks.
Season	August to November.
Occurrence	Infrequent; rare in many areas.
Similar species	Agaricus haemorrhoidarius is very similar, with grey-brown scales and a stouter stem; it occurs under broad-leaved trees, notably oak and beech.