Russula sardonia, commonly known as the primrose brittlegill, is a mushroom of the Russula genus, which are commonly known as brittlegills. The fruiting body, or mushroom, is a reddish-purple, the colour of blackberry juice, and is found in coniferous woodland in summer and autumn. It is inedible, and like many inedible members of the genus, has a hot, peppery taste.