Rock Moss

Rock moss, Andreaea rupestris, is a moss of the family Andreaeaceae, part of the small class Andreaeopsida, a basal lineage among mosses distinguished by capsules that split open along four vertical lines rather than through a lidded opening as in most other mosses, and by lacking the stalk, or seta, that raises the capsule in typical moss species. Dark reddish-brown to black, it grows in dense cushions on acidic, exposed rock such as granite from sea level to high elevation across much of the Northern Hemisphere, including Canada, the United States, Norway, Britain, Ireland, China and Japan.