How to tell Birch knight from Yellow knight

The cap is 4–12 cm across, occasionally up to 15 cm. Young caps are convex, then flatten, often with a low umbo, and can be slightly sunken in the centre.

The colour is reddish brown to yellowish brown: darker in the centre, paler and yellowish at the margin. Fine brown fibres radiate from the centre. The skin is sticky, slimy and shiny in wet weather and matt when dry. The margin is often grooved, and old caps may crack into small scales.

The cap is 4–12 cm across, flat-convex or with a low hump in the centre. It's yellowish green or olive yellow, dry or slightly moist, and often darker in the centre, with characteristic small fibrous scales. The margin is uneven and wavy.

The gills are crowded, fairly broad and notched where they meet the stem. Young gills are pale yellow or yellowish white, and with age they develop rusty brown spots, with brownish edges.

Yellowish gills are unusual in the genus: most knights, including the poisonous brown ones, have white or cream gills. The spore print is white.

The gills are crowded and yellow or yellow-green (the same colour as the cap or brighter); yellow gills are one of the key identification features. They're attached to the stem. The spore print is white.

The stem is 4–13 cm tall and 0.7–2 cm thick, cylindrical, sometimes thickening towards the base. It's coloured like the cap but paler, yellowish brown, lighter at the top, and streaked with darker brown lengthways fibres.

Young stems are solid and slightly sticky; old ones become hollow. There is no ring and no volva.

The stem is 4–8 cm tall and 1–2 cm thick, firm, solid and cylindrical, yellowish or yellow-green, and partly buried in sand. There's no ring and no volva.

The flesh is firm. It's whitish to pale yellow in the cap and distinctly yellow in the stem, and that's the easiest way to tell the birch knight from other brown knights, whose flesh is white. It doesn't change colour when cut. The taste is mealy, sometimes slightly bitter.

The flesh is firm, white or slightly yellowish, and doesn't change colour when cut. The taste is mild, mealy or slightly radish-like, with no bitterness.

The smell is mealy, like raw dough, sometimes with a hint of cucumber. It's not much help for identification: some poisonous brown knights smell of flour too.

The smell is mealy, slightly like cucumber or radish, as in many Clitocybe and Tricholoma species, with nothing unpleasant about it. In some mushrooms it's stronger and recalls fresh flour.