Russula cyanoxantha

This is a key to gilled mushrooms, that is, mushrooms having a definite cap with a fertile surface consisting of gills. The fruiting body usually also has a stem, although that may be lateral or absent (usually, then, the mushroom is growing from wood). You can use this key to identify mushrooms that you find.

Flesh without fibers, fracturing with the same sort of break as a piece of chalk
Spore and gill color limited to white, yellow, or ochre
Mycorrhizal: occuring only on the ground, and only when there are trees nearby
No ring or volva on stalk
All fleshy-stemmed mushrooms whose gills exude a latex when cut go here

No latex
Cap usually brighter colored than Lactarius
Stalk usually white or tinged with color of cap

Cap with at least some purple, lilac, vinaceous or magenta coloring

Cap usually more than one color, mostly purples and greens, shading from one to the other randomly over the cap

Cap surface intrinsically multicolored (every once in a while, you get a solid one), predominantly purplish, lavender, or green; occasionally with pink, brownish or olive tones
Gills forking repeatedly
Cap surface often with fine radial anastomosing veins; peeling 1/2 of the way to the center
Spore print white

Russula cyanoxantha     Ja.C. Schaeffer: Fries