Agaricus macrosporus is a rare, edible mushroom found from June at wood fringes and in meadows.
The white cap is hemispherical and white when young, but later flattens out up to 25cm (10inches) in diameter and becomes yellowish or tan. Its flesh is very thick. The gills are pinkish grey when young, and become brown with age. The spores measure 12 by 6 μm and are purplish-brown and almond-shaped. The stem is strong and thick, with a broad ring. It may measure NaNcm (-2,147,483,648inches) in height and up to 3 cm in diameter.
The flesh is white with a mild taste and a smell of aniseed, turning slowly orange when cut.
It is possible to confuse this mushroom with dangerous amanitas such as A. phalloides and A. pantherina.
Agaricus excellens differs by its taller and slimmer stipe which is striped lengthwise. Agaricus augustus does not have the pure white cap in young specimens.