Musci (mosses; division Bryophyta) A class of plants all of which have a gametophyte that is differentiated into stem and leaves. The leaves are generally only 1 cell thick (except at the midrib); they are never stalked. The leaves may be finely toothed or entire; they come in a variety of shapes but are never deeply lobed, differing in this respect from some leafy liverworts. Most mosses are either acrocarpous or pleurocarpous. Mosses can be found in a wide range of habitats, growing on rocks, soil, tree bark, etc. Their distribution is cosmopolitan.

Musci See Bryophyta.