Russula fragilis  Fr. (1838)                          *Collections: British Columbia, California, Colorado and Oregon

As it is typical for the Genus, Russulas fragilis displays variable colors that are easier to show than to describe, but the combination of purple, olive and reddish colors, in conjunction to a white stipe (without pinkish flush), white spores and an acrid taste define the specie. In my experience, it is far more common in the Northern temperate forests of British Columbia and Washington State  than in California.  In general North American collections seem to exhibit much higher warts than  described from Europe and may easily be a variety.

Western American collections seem to have higher warts than described from Europe. Harry Thiers' spore drawing (Agaricales of California: Russulaceae) vs. an actual photo of the spores from a local collection. Favorite of the slugs too

European collections