How to tell Salty mushroom from Death cap

The cap is 6–15 cm across and very fleshy. Young caps are hemispherical, then convex and flattened, and the margin stays inrolled for a long time.

The skin is white, cream or greyish, dry and smooth at first, often with brownish spots. With age it cracks into coarse brownish scales and furrows, so the cap looks like cracked earth. Mushrooms often come up already dirty, with sand or soil on the cap.

The death cap's cap is 5–15 cm across, hemispherical when young, then opening out flat.

Its colour ranges from olive green and yellowish green to greyish and almost white, which is exactly what makes it tricky to identify. The surface is smooth and a little slimy in wet weather, with a characteristic pattern of darker fibres radiating from the centre. The margin is even, with no striations.

The gills are free, meaning they don't reach the stem, and very crowded. In young mushrooms they are greyish pink or pink, then reddish brown, and chocolate in mature ones. They are never white in a mature Agaricus.

The spore print is chocolate brown. A white print means it isn't an Agaricus.

The gills are crowded, thin and free, meaning they don't touch the stem. They're white and may turn creamy with age, sometimes with a faint pinkish tinge, but they never turn chocolate brown.

It never has the chocolate-brown gills of a mature Agaricus. The gap between gills and stem is clear. In young mushrooms a white, membranous veil covers the gills completely.

The stem is 4–10 cm tall and 2–4 cm thick, white, firm and solid. It's usually shorter than the cap is wide, which makes the mushroom look squat.

There is a single narrow, sleeve-like ring with an upturned edge; in young mushrooms it is thick and rubbery. There is no sac (volva) at the base. The base often sits deep in the soil, so dig the mushroom up whole to check it.

The stem is slender, 7–15 cm tall and 1–2 cm thick. It's cylindrical and swells at the base into a characteristic club-shaped bulb wrapped in a membranous, sac-like volva. That volva is the main diagnostic feature.

It's whitish green, often with a faint, banded snakeskin pattern. A well-developed white ring, left over from the veil, hangs in the upper third. Below the ring the surface is faintly scaly.

The flesh is thick, firm and white. When cut or pressed it reddens, turning orange-red or reddish brown, sometimes vividly, sometimes slowly and only faintly. It never turns yellow. The taste is mild, slightly salty according to some.

The flesh is white and doesn't change colour when cut, and that's the treacherous part: none of the safety signs foragers usually rely on work here. It's thin and brittle in the cap, thicker and firmer at the base of the stem.

It doesn't darken in the air, not after a minute and not after an hour. Don't let "lovely white flesh" reassure you: the white flesh of the death cap is exactly where amanitins are most concentrated.

Descriptions of the smell vary: briny, fishy, unpleasant, and some authors also notice a hint of aniseed. That is where its German and French names meaning smelly mushroom come from. Treat the smell as a hint only: the reddening flesh, the pink to chocolate gills and the single ring decide. A strong smell of ink or carbolic points to the poisonous yellow stainer.

Fresh, it has a faint smell that's easy to miss, and young ones barely smell at all. Mature mushrooms pick up a slightly sickly-sweet note, like wilted honey or stale dough.

That smell isn't strong enough to warn an inexperienced forager. Like other poisonous amanitas (the fly agaric, the panther cap), the death cap smells faint and nondescript, so it gives you no warning at all, which is one more treacherous trait. Only rotting mushrooms smell any stronger.