How to tell Butter cap from Wood pinkgill

The cap is 3-7 cm across, convex when young, opening out with age to flat with a small umbo in the centre (a characteristic shape). The cap skin is smooth, with a pronounced buttery-greasy sheen in wet weather, hence the name. It's strongly hygrophanous: in wet weather dark chestnut-brown in the centre and lighter toward the margin; when dry, light creamy brown to ochre and faded. The margin is even and thin, often with lengthwise striations where the gills show through.

The cap is 3–10 cm across and fairly thin-fleshed. Young caps are convex or bell-shaped, then flatten with a low, broad bump; in old mushrooms the centre sinks slightly, leaving the bump in the middle.

The colour is grey-brown, beige, yellowish grey or olive-grey. The cap is hygrophanous: dark when wet, with faint lines at the edge, fading almost to off-white as it dries, often in patches. The surface is smooth, a little sticky in damp weather and silky-shiny when dry.

The gills are adnate or free from the stem, crowded, thin, whitish to cream, turning cream-pink with age. The spore print is pale pink to cream, a typical trait of the genus Rhodocollybia ("pink Collybia").

The gills are attached to the stem, sometimes running slightly down it, and moderately spaced. They are white in young mushrooms, turn pink with age and become dull pink in old ones.

The spore print is pink. This is what separates a pinkgill from grey knights, domecaps and funnels, which all leave a white print.

The stem is 3-7 cm tall and 0.3-0.8 cm thick, cylindrical and noticeably thickening toward the base (often with a characteristic "root" running down into the substrate). It's ochre-brownish, darker toward the base, with a smooth surface and lengthwise fibres. The stem flesh is tougher and more fibrous than the cap's.

The stem is 4–10 cm tall and 0.5–1.5 cm thick, white or greyish, smooth and silky, with fine lengthwise fibres. It is stuffed at first, then becomes hollow and brittle and is easily crushed between your fingers.

There is no ring, no veil remnants and no volva. The very base can have a little white mycelial fluff.

The flesh is thin and tender in the cap, tough and fibrous in the stem, whitish to cream, and it doesn't change colour when cut. The smell is faintly mushroomy, the taste mild and neutral, normally without bitterness.

The flesh is white, thin and brittle, doesn't change colour when broken and has no milk. The taste is mild or mealy, not bitter.

Faint, neutral, mushroomy, nothing distinctive.

The smell is indistinct or faintly of flour; in the smelly form (Entoloma nidorosum) it is sharp and chemical, like bleach or ammonia. Drying mushrooms smell unpleasant. Don't rely on smell: the edible mushrooms it is mistaken for smell of flour as well.