Crab brittlegill or Bloody brittlegill

The cap is 5-15 cm across, hemispherical when young, becoming flat and spreading with a slightly depressed centre with age. The cap skin is matte, slightly sticky in wet weather, dry and matte in dry weather, and peels easily 2/3 of the way to the centre. It's wine-red, purple-violet, burgundy in the centre, paler toward the edge, fading to pinkish-grey and ochre. Mature caps have fine radial grooves at the edge.

The cap is 4–10 cm across. Young caps are domed, then convex, later flat, sometimes with a shallow dip in the centre or saucer-shaped.

The colour is blood red, wine red or purplish red. As it ages the cap fades unevenly, with pink, cream or almost white patches. It is matt when dry and sticky with a silky sheen after rain. The skin holds tight and only peels as a narrow strip at the edge. That's a useful clue: on the sickener you can peel the skin almost to the centre.

The gills are attached or free from the stem, moderately crowded, fleshy and brittle. They're cream-white when young, becoming ochre-yellow to yellow-brown with age as the spores mature. Spore print yellow-ochre to yellow-brown.

The gills are fairly crowded, narrow and brittle, often forked near the stem. They are attached to the stem or run slightly down it, which few red brittlegills do. They start white or cream and turn straw-coloured or pale ochre.

The spore print is cream to pale ochre. A pure white print points to the sickener; a deep ochre one to the hintapink or Russula integra.

Stem 5-10 cm tall, 1.5-3 cm thick, firm, fleshy, cylindrical, hollow inside in old mushrooms. It's white when young, with a characteristic pink or wine-coloured tint, and where pressed or cut it slowly turns yellow, then brown, a diagnostic feature. Surface smooth with fine lengthwise wrinkles. No ring.

The stem is 3–7 cm tall and 1–3 cm thick, cylindrical and firm, sometimes hollow in old specimens. There is no ring and no volva.

The key feature of the species is the stem colour: a pink, wine-red or red flush, strongest towards the base, with fine lengthwise streaks. Young stems can still be white, and old ones turn greyish pink with a yellowish base. A pink stem alone doesn't prove the species, since the hintapink, the rosy brittlegill and the crab brittlegill can have one too.

Flesh firm, brittle, white; it slowly turns yellow when cut, then brownish over time (especially in the stem), a characteristic reaction of the species. The smell is distinctly fishy and briny (smoked herring, shrimp, fish) and is the main diagnostic. Taste mild, nutty, with no bitterness or acridity.

The flesh is white and firm, reddish under the cap skin, sometimes yellowish at the stem base, and yellows a little with age. It barely changes colour when broken and has no milk. Field guides describe the taste as hot, peppery and often bitter, milder in the stem. There's no need to taste mushrooms: the other features are enough to identify it.

Distinctly fishy and briny: smoked herring, cooked shrimp, fish. A diagnostic feature of the species, easy to notice when you cut it and still there in the finished dish.

The smell is faint and fruity, sometimes hardly noticeable. It lacks the strong crab or herring smell of the crab brittlegill.