Coprinus sterquilinus:

These are often mistakenly called Shaggy Manes.  They are a close relative of C. comatus, but the true Shaggy Mane grows in association with buried wood.  C. sterquilinus grows in association with cow/horse dung and grows in the spring ( around Morel Time in TN) in cow/horse pastures.  They are a little smaller and deliquesce at a faster rate than C. comatus, but are equal in everyway.  If you will put them  in ice water and set them in the refrigerator, they will keep for a day or so.  They are a real good edible and fairly common in Tennessee.