In the photo above, the differences between Lactarius deceptivus and Lactarius piperatus are fairly evident.
Lactarius piperatus has a large, dry, crumbly, chalky, nearly smooth, velvety cap that is depressed in the center. Its smooth margin in initially inrolled, but as the mushroom matures, it develops a funnel shape. The gills are somewhat decurrent, thin, narrow and very crowded. The latex is white. It has a peppery taste. Its spore print is white. Lactifluus piperatus is mycorrhizal with both hardwoods and & conifer trees situated in well-drained soil. The similar-looking Lactarius deceptivus has cottony inrolled margin.