MOSSES (Musci), a class of cryptoganmus plants, forming with the liverworts (Hepattcee) the group Muscinece or Bryophyta. The only plants likely to be wrongly called mosses are the foliose liverworts, and these are readily distinguished by their two-ranked nerveless leaves, their four-valved capsule and certain other characters. A germinating moss spore gives rise to a filamentous body called a pro toner's°, from which buds arise and develop into the leafy shoots which constitute the true moss-plants. After a time the reproductive bodies are formed at the tips of certain shoots. The antheridia, or male reproductive organs, are club-shaped and contain cells which after ward develop into the antherozoids. These antherozoids, when liberated from the anther idium, move about until they come in contact with an archegonium, or female reproductive body. The fertilized archegonium is then car tied upward on a slender filament or seta, and now forms the fruit or capsule, usually closed by a lid or operculum, and often covered by a sort of hood called a calypira. When ripe the capsule opens and liberates the spores, which by germination begin the life-history again. Mosses may also reproduce asexu ally by the formation of buds or gemme. There are no true roots in mosses and the leaves are of very simple structure. New ones are con tinually springing from old shoots, so that in bogs the top remains growing while the under layers die and the deeper ones slowly change into peat. Some 5,000 species of mosses are
known, of which about nine-tenths belong to the order This order comprises the two suborders, Clesstocarpce, with an indehiscent capsule, including the genera Phascum, Ephe merum, etc., and Stegocarpe, in which the cap sule opens by a lid. The stegocarpous mosses, again, may have the capsule either terminal (Acrocarpce) or lateral (Pleurocarpce), the former group including, among others, the genera Grimmia, Fusidens, Polytrichum, Ortho trichum, Dicranum, Mnium, Bryum and Fu naria, and the latter, Hypnum, Leskea and Climacium. There are three other orders of mosses, namely, Sphagnacea', or Bog-mosses, with only one genus, Sphagnum; Andrecracee, with the single genus Andreeca, and Archi diacee, with the genus Archidium. Mosses are of little or no economic value, but they form an important part of the natural covering of rocks and serve to prepare the way for higher forms of plants. Consult Campbell, 'Mosses and Ferns' (New York 1895) ; Grout, A. J., 'Mosses with a Hand-Lens' (2d ed., New York 1905); Hale, E. H., 'Flowerless Plants' (New York 1909); Strasburger, 'Textbook of Bot any' (1903).