http://www.sciencedaily.com/releases/20 ... 191621.htm
Kunstformen der Natur (1904), plate 72: Muscinae by Ernst Haeckel (1834–1919
.ScienceDaily (June 3, 2012) — In cities, the presence of algae, lichens, and mosses is not considered desirable and they are often removed from roofs and walls. It is, however, totally unfair to consider these cryptogamic covers, as the flat growths are referred to in scientific terms, just a nuisance. Scientists at the Max Planck Institute for Chemistry have discovered that these mostly inconspicuous looking growths take up huge amounts of atmospheric carbon dioxide and nitrogen and fix it at Earth's surface.