A white mushroom with a smooth round cap from 2 1/2 to 4 inches wide. Like all members of this family it has white gills that are free from the stalk. The gills change from pink or white to chocolate brown as the mushroom ages. The stalk is about 3 inches to 6 inches long. There is a ring on the stalk. This mushroom was identified by Dr. Tom Weber a mycologist at the University of Nebraska Omaha. It has all the characteristics of Agaricus and he feels reasonably certain it is A. silvicola. In late August,2013 hundreds of these mushrooms in several groups were found beside cottonwood trail between the parking lot and stream trail. At the time of discovery they were probably young ones as the gills were white. A couple of these groupings are shown in photos C. and D.