A class of plants within the Bryophyta comprising the mosses, which are found in both damp (including freshwater) and drier situations. Mosses possess erect or prostrate leafless stems, which give rise to leafless stalks bearing capsules. Spores formed in the capsules are released and grow to produce new plants. (Concise Dictionary of Biology, 1990). Many small plants bearing the name moss are in fact not mosses. The "moss" found on the north side of trees is actually a green alga (ALGAE, GREEN). Irish moss is really a red alga (ALGAE, RED). Beard lichen (beard moss), Iceland moss, oak moss, and reindeer moss are actually LICHENS. Spanish moss is a common name for both LICHENS and an air plant of the pineapple family (BROMELIACEAE). Club moss is an evergreen herb of the family LYCOPODIACEAE.