Polytrichum commune. A rich tuft of bright green Polytrichum commune moss seen from directly above. This moss is common in wet moorland and by wood- land streams, where it grows in luscious green clumps before shedding spores. Damp conditions are necessary because mosses have no true roots, depending instead on their leaves to absorb water and minerals. Sexual reproduction also requires moisture because the male sperm must migrate to the female cells via a film of water on the plant's surface.