a cryptogamous plant of a cellular structure, with distinct stem and simple leaves. the fruit is a small capsule usually opening by an apical lid, and so discharging the spores. there are many species, collectively termed musci, growing on the earth, on rocks, and trunks of trees, etc., and a few in running water.-a bog; a morass; a place containing peat; as, the mosses of the scottish border.-to cover or overgrow with moss.