The blackening russula (Russula albonigra) is a thick mushroom displaying the shape of a milk-white brittlegill (R.delica) but the cap cuticle cap is coloured in a blur of almost black dark grey and white.
The cap is robust, up to 12 cm in diameter, depressed in the centre and with involute margins. The white colour predominates on the cap surface of young mushrooms, but black expands as the individual grows. The gills are white colour and dense. The stem is short, thick, solid and white coloured like the gills. The flesh is white colour and hard. When the flesh is cut or the gills or the stem are rubbed, the initial white colour darkens until black as coal; that’s why the popular English name of blackening russula.
The blackening russula pops up in autumn in the grassy clearings of mixed pine, holm and oak forests. It is a rare mushroom in the central counties of Catalonia.
[photo Jordi Badia]