Mosses come in a wide variety of forms, but all are based on a stem and leaf structure.
The stem may be branched to a greater or lesser degree. Broadly, they can be divided into two groups - acrocarpous and pleurocarpous mosses. Further growth takes place via branches off the main stem. An example of an acrocarpous moss is Bryum pseudotriquetrum . Pleurocarpous mosses have a main stem of unlimited growth , and usually much-branched.