Russula claroflava, also known as Yellow Swamp Brittlegill, is a brightly coloured agaric that has a convex to flat, vivid yellow cap. It grows with birch in very damp or boggy woodland.

Cap bright yellow in colour, which diminishes with age, and slightly sticky when damp. It has thin, smooth skin that can easily be peeled off and often a depressed center. Gills at first white, then creamy yellow. Older ones can have grey or black edges, more or less free or reaching but not connected to the stem and fairly crowded. Stem is white, turns grey with age, more or less equal, fairly stout, and smooth. The mushroom has no ring.

Similar species Russula claroflava has a stem that grays strongly on bruising. Russula ochroleuca has a green tinge on the cap. Russlula ochroleucoides is a bitter-tasting American equivalent, growing in East Coast oak woods.

Russula claroflava on the www.first-nature.com web site.