Both mosses and lichens depend upon external moisture to transport nutrients. Because of this they prefer damp places and have evolved special methods of dealing with long dry periods. Higher plants, on the other hand, have specialized organs for transporting fluid, allowing them to adapt to a wider variety of habitats. Bryophytes used to be classified as three classes of a single phylum, Bryophyta . This reflects the current taxonomic wisdom that the Liverworts and Hornworts are more primitive and only distantly related to Mosses and other plants.
All plants reproduce through alternating generations.
Nowhere is this more apparent than in the mosses. The first generation, the gametophyte , forms the green leafy structure we ordinarily associate with moss. The moss sporophyte is typically a capsule growing on the end of a stalk called the seta . As the sporophyte dries out, the capsule release spores which will grow into a new generation of gametophytes, if they germinate. While people typically know what a moss is, few have even heard of liverworts and hornworts.