Russula sericeonitens Kauffman.
Cap 4-6cm across, convex then depressed; deep violet-purple, almost black at center; smooth, silky, shining; peels easily. Gills subdistant, broad; white. Stem 30-70 x 10-15mm, equal; white. Flesh soft; white. Odor none. Taste mild. Spores ovoid, 7-8 x 6-7µ; warts up to 1.2µ high, isolated. Deposit white (A). Habitat in mixed woods. Occasional. Found in eastern North America, west to Michigan. Season July-September. Edible (Never eat any mushroom until you are certain it is edible as many are poisonous and some are deadly poisonous.)