Mosses have several characteristics that distinguish them from other bryophytes. Only mosses have a multicellular rhizoid, a root-like subterranean tissue that absorbs water and nutrients from the soil. Liverworts and hornworts have single celled rhizoids. Mosses have radial symmetry, in that a cut down the long axis of an individual gives two similar halves. Hornworts and mosses are unique bryophytes in that they have stomata, cells specialized for photosynthetic gas exchange, on their sporophytes. Liverwort sporophytes lack stomata. In addition mosses do not have true leaves or stems. Their leaf-like structures are called phyllids. They are typically only one cell thick, although phyllids in some species are several cells thick.
Science EncyclopediaScience & Philosophy: Molecular distillation to My station and its duties:Moss - Bryophyte Characteristics, Moss Characteristics, Life Cycle, Habitat And Ecology, Evolution, Importance To Humans