Whitish cap with dark brown scales that look like they are peeling away. Rounded dome like cap. Deep white gills. Long stem which tapers from a thick (0.5 - 0.75 inch) wide bulbous base up to a narrow connecting point (0.25 inch) with the cap. Gills do not touch the stem. Spores are white (not green like Cholorphylum molydites).
Growing under the drip line in a circle around Colorado blue spruce and ponderosa pine trees. Found some under elm trees also. Growing in the dirty grassy margins of the tree and some slightly further out in the grassy area between pines.
Suspect Lepiota rachodes