Agaricus arvensis Schaeff. ex Secr. s. Lange non Cooke syn. Psalliota arvensis (Schaeff. ex Secr.) Kummer. Horse Mushroom, Agaric des jachčres, Boule de neige, Anischampignon, Erdőszéli csiperke, Prataiolo, maggiore, Anijschampignon, Akkerchampignon. Cap 8–20cm across, ovate at first expanding convex, creamy white yellowing slightly with age or on bruising. Stem 80–100 x 20–30mm, often slightly clavate at the base, concolorous with the cap, the ring is formed of a double membrane, the lower splitting into a star-shape around the stem. Flesh white, thick and firm in the cap, pithy in the stem which tends to become hollow. Taste mushroomy, smell of aniseed. Gills free, white at first then flesh-pink, finally chocolate brown with age. Cheilocystidia thin-walled, ovate balloon-shaped 11–26 x 9–18(21)µ. Spore print dark purple-brown. Spores ellipsoid, 7–8 x 4.5–5µ. Habitat amongst grass in pasture or thickets often in rings. Season autumn. Frequent. Edible – excellent. Distribution, America and Europe.