This small, white-flowered plant was unknown in Maryland until discovered by a Maryland Natural Heritage Program ecologist in 1989.

Appalachian Sandwort, Mononeuria glabra​, flowers in July on open areas underlain by basalt or granite. The plant is scattered throughout the upper latitudes of the northern hemisphere, but this basalt glade on Catoctin Mountain is its only know location in Maryland, where it is listed as State Endangered.

Finding and monitoring unique habitats and species, such as the Appalachian Sandwort, are the primary responsibility of the Maryland Natural Heritage Program. This field work provides the basis for further research and protection efforts.