What do mosses lack – what do ferns have?

Mosses are practically the most undeveloped of terrestrial plants. Although both mosses and ferns reproduce by spores, ferns are much more advanced plants than mosses. Moss has only one vessel, unlike ferns, which have many. The vessels are thin tubes through which the leaves of the plant receive water and nutrients from the roots. The more vessels, the trunk and stems of the plant can become thicker and stronger and grow taller. Ferns also have branches and leaves, while mosses do not.