Rock Spikemoss is a plant species belonging to the clubmoss family. It is also known by various other names that include rock-brake, mountain lesser clubmoss, rock selaginella, and Appalachian spikemoss. These synonyms are based on the plant's habitat and physical attributes. The name "rock-brake" comes from the fact that it grows on rocky surfaces, while "mountain lesser clubmoss" denotes its small size and club-like appearance. The name "rock selaginella" is derived from the plant's common name, selaginella, which is a genus name for clubmosses. Lastly, "Appalachian spikemoss" refers to the plant's natural distribution in the Appalachian mountains.