The Clay-Gilled Milkcap (Lactarius argillaceifolius) is a mycorrhizal mushroom that can be found growing on Oak forests in the summer. This one was found growing alone in low open mixed Oak/Hickory woodland near Northern Red Oak, Ash, and American Hophornbeam trees at Indian Cave State Park in southeastern Nebraska. It's well camouflaged in its environment and easily blends in with the surrounding leaf duff and woodland debris.

The cap is dull colored, flat to depressed in the middle and the surface is tacky, often adhering to leaves as if attached by glue. The gills are attached and running down the stem (decurrent) and are cream-colored becoming darker with age. The stem tapers at the base. When cut, it exudes a cream-colored latex, which later turns dark gray, producing the same color when the mushroom is bruised. The taste is peppery/spicy (acrid). The spore print is pale-yellow.