Sedum glaucophyllum
Sedum glaucophyllum, the cliff stonecrop, is a species of Sedum native to the Appalachian Mountains in the eastern United States from West Virginia, Maryland, Virginia and North Carolina.

Sedum glaucophyllum is a prostrate, mat-forming evergreen perennial plant forming patches up to  in diameter. The leaves are glaucous green, succulent, rounded,  long and wide, arranged in a dense helix on the stems. The flowers are white,  in diameter, with four slender, pointed petals; they are produced in clusters on erect stems up to  tall, held above the foliage.

References

Flora of the Eastern United States
Plants described in 1946
glaucophyllum