How to tell Greasy green brittlegill from Death cap

The death cap's cap is 5–15 cm across. In young mushrooms it is hemispherical, later becoming flat and spread out.

The color varies from olive green and yellowish green to grayish and almost white — which is what makes identification tricky. The surface is smooth, slightly slimy in wet weather, with a characteristic radial pattern of darker fibers spreading from the center. The cap margin is even, without striations.

Cap 5-12 cm across, when young convex with an inrolled margin, with age becoming flattened with a slightly depressed center. The cap skin is smooth, slimy in wet weather, dry and matte in dry weather, peels easily 2/3 of the way to the center. Color green-olive, olive-gray, gray-brown, deeper in the center to dark green. Mature caps have fine radial grooves at the margin.

The hymenophore is lamellate. The gills are crowded, thin and free — not attached to the stem. In both young and mature mushrooms they stay pure white — this is a critical diagnostic feature.

Not a hint of pink, cream or ochre, as in true Agaricus mushrooms. The gap between the gills and the stem is clearly defined. The veil is white and membranous, completely covering the hymenophore in young specimens.

Gilled hymenophore — gills adnate or free from the stem, moderately crowded, thin, with characteristic forking near the stem — a diagnostic trait. Color pure white to creamy white. Spore print white.

The stem is slender, 7–15 cm tall and 1–2 cm thick. Cylindrical, widening at the base into a characteristic club-shaped bulb wrapped in a membranous sack-like volva — the main diagnostic feature.

The color is whitish green, often with a snakeskin pattern of faint bands. In the upper third there's a well-developed, hanging white ring with remnants of the veil. The surface below the ring is faintly scaly.

Stem 4-8 cm tall, 1.5-2.5 cm thick, firm, cylindrical, hollow in old specimens. Color white to cream, with faint gray-cream patches in old specimens. Surface smooth with fine lengthwise wrinkles. No ring, no volva.

The flesh is white and doesn't change color when cut — and that's the treacherous part: none of the safety signs foragers are used to relying on work here. The flesh is thin and brittle in the cap, fleshy at the base of the stem.

It doesn't change color on contact with air, neither after a minute nor after an hour. No "lovely white flesh" should reassure you — it's precisely in the white flesh of the death cap that the concentration of amanitins is highest.

Flesh firm, brittle, white, turns faintly pink when damaged — a reaction typical of the species. Smell faint, pleasant, fruity-mushroomy, taste mild, sweetish and nutty, not bitter (tongue test).

The smell of a fresh mushroom is faint and hard to notice; in young specimens it's almost absent. Mature ones develop a slight sickly-sweet note, like wilted honey or stale dough.

This aroma isn't distinct enough to warn an inexperienced forager. Like other poisonous amanitas (the fly agaric, the panther cap), the death cap has only a faint, indistinct smell that gives no warning — yet another treacherous trait. A stronger odor appears only in rotting specimens.

Faint, pleasant, fruity-mushroomy, neutral-sweetish.