Calocybe gambosa (Fr.) Sing. syn. Tricholoma gambosum (Fr.) Kummer syn. Lyophyllum georgii (L. ex Fr.) Kühn. & Romagn. Mairitterling Tricolome de la Saint-Georges, Mousseron vrai St George’s Mushroom. Cap 5–15cm across, subglobose then expanding, often irregularly wavy and sometimes cracking, margin inrolled, white. Stem 20–40×10–25mm, white. Flesh white, soft. Taste and smell mealy. Gills narrow, very crowded, whitish. Spore print white. Spores elliptical, 5–6 x 3–4µ. Habitat in grass on roadsides and wood edges or in pastureland. Season found traditionally on 23 April, St George’s Day, whence it gets its name although more frequently maturing a week or so later. Occasional. Edible – good. (Never eat any mushroom until you are certain it is edible as many are poisonous and some are deadly poisonous.) Distribution, America and Europe.