How to tell Dog stinkhorn from Death cap

There's no separate cap. The top of the stem is pointed, orange-red and finely bumpy, and only the tip is covered in sticky, shiny dark olive slime that carries the spores. Once flies have eaten it, the tip shows bright orange.

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.

There are no gills or pores: the spores are carried in the olive slime at the tip. There's no ordinary spore print; the spores are pale yellow in mass.

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 6 to 15 cm tall and about 1 cm thick, cylindrical, hollow, spongy and pitted like expanded polystyrene, white, pale yellow or pale orange, often curved and fragile.

At the base the remains of the egg form a white sac (volva) with white mycelial cords. The young fungus looks like a white or yellowish egg 2 to 3 cm across, half buried in leaf litter.

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 stem walls are spongy like polystyrene, whitish to pale orange. Inside the egg, a layer of clear jelly lies under the skin.

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.

The smell is unpleasant and carrion-like, but much weaker than the common stinkhorn's.

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.