How to tell St George's mushroom from Deadly fibrecap

The cap is 3-10 cm across, hemispherical to convex in young mushrooms, with a broad umbo in the center; it opens out with age. The surface is silky-shiny, with fine radial fibers and flattened scales. At first the color is whitish, cream or ivory; with age and when touched it slowly turns red — first pinkish, then brick-carmine or cinnamon-red. The reddening is most visible along the cap margin and wherever the mushroom is damaged. This is the key diagnostic feature.

The cap is 5-15 cm across (large, fleshy); when young it is hemispherical with an inrolled margin, with age becoming flat-convex, and in old specimens flat and spread out with a wavy margin. The skin is smooth, dry and matte in wet weather, with a fine felty fibrousness. Color: creamy white, ochre-cream, with a faint brownish tint at the center; in old specimens creamy ochre. The margin is even — inrolled when young, wavy and irregular when old.

Gilled hymenophore. The gills are fairly crowded, notched where they meet the stem. In young mushrooms they are whitish-pinkish, with age olive-brown to brick-brown. The spore print is olive-brown or tobacco-colored — typical of the whole genus Inocybe.

Lamellate hymenophore: the gills are notched (emarginate) at the stem, very crowded, thin, fleshy. Color: pure white to creamy white, with no pink or green tint — a diagnostic feature (it sets the mushroom apart from the poisonous Entoloma sinuatum, whose gills turn pink). Spore print white.

The stem is 3-10 cm tall and 0.5-1.5 cm thick, cylindrical or slightly widening toward the base. It's whitish to cream, with a pink or reddish-brick tinge (especially in the lower part). When touched and with age it turns red, just like the cap. The surface is lengthwise-fibrous, with no ring. The flesh of the stem is firm.

The stem is 3-7 cm tall, 1.5-3 cm thick — much shorter and thicker than the cap is wide (hence gambosa — "short-legged"). Cylindrical, thickening toward the base, firm, fleshy. Color: white to creamy white. Surface: smooth, with fine lengthwise fibers in the lower part. No ring.

The flesh is thick and white; when cut, it slowly turns red (not right away: sometimes only after 30 minutes or more), especially in the lower part of the stem. This is an important way to tell it from most Agaricus mushrooms, whose flesh either doesn't change color or turns yellow (though some wood mushrooms, such as Agaricus silvaticus, also redden, so check the gills and spore print too). The smell and taste of the fresh flesh are pleasant, fruity and sweetish — which is exactly what makes it so treacherous.

The flesh is very firm, fleshy, pure white. It does not change color when cut. Smell: distinctly mealy, sharp and characteristic (like freshly milled flour or dough); taste sweetish and nutty, with no bitterness.

Sweet and fruity, with notes of ripe pears or apples — unusual for the genus Inocybe, which usually smells spermatic or musty. This appealing aroma + a reddening white cap + the season when edible white mushrooms are being picked = the perfect trap for a beginner forager. Never rely on smell when identifying this species.

Distinctly mealy, like freshly milled flour or raw dough — a diagnostic feature, easy to notice on a cut surface.