Hydropunctaria orae

Hydropunctaria orae is a species of saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. It is a marine lichen. It forms thin, dull mid-green to dark greenish-grey crusts on coastal rock surfaces, particularly in areas that receive slight moisture from rainfall. Although difficult to distinguish from related species without DNA analysis, it can be identified by its green cortical pigments and minutely roughened surface texture. Initially known only from two localities in the British Isles, the species was later discovered in southwestern Norway in 2014. It occupies specific ecological niches within coastal environments, including both seashore rocks and stones in freshwater streams near the shore....read more on Wikipedia.