The Cottony-margined Milky Cap is a large mushroom, 2-9 inches wide. The short, fat stem is distinctively characteristic at 1-3 inches tall. The center is slightly depressed and the stem is often offset from center. The cap has a cottony rolled-under edge; the gills running down the stem. The stem is velvety; all parts white (tan or brown with age or from bruising). The overall color is mily white. The entire mushroom slowly stains tissue brown. The spores are white.

Its preferred habitat is under confiers, or in mixed woods, and tended lawns.