The poisonous Clitocybe dealbata
also grows in grassy areas, also forms fairy rings, and also has a white spore deposit. It differs in that the cap is whitish and lacks a central hump, the gills are more closely spaced, and the stem is hollow and stiff rather than solid and pliant/tough. A number of other species are superficially similar but lack the distinctively tough and pliant stem and/or do not form fairy rings in grass. For example, many poisonous species of Inocybe
differ in that the cap has a sharper central bump, the cap is usually split radially, the stem is not as tough, the spore deposit is brown, and it does not form fairy rings in the grass.