There are many types of nonvascular plants, including mosses, lichens, liverworts, hornworts and algae. Algae can be further divided into three separate phylum: Chlorophyta or green algae, Rhodophyta or red algae, and Phaeophyta or brown algae. This last family also includes kelp and some species of seaweed.
Mosses belong to the phylum Bryophyta, which is the largest group of nonvascular plants with more than 10,000 known species. Although they are nonvascular, mosses do have a simple leaf-and-root structure. There are more than 6,500 known species of liverworts, all of which have a much more basic structure than mosses. Hornworts are the smallest phylum, as only around 100 species have been classified.
All nonvascular plants have a very simple internal structure that lacks the ability to transport water within it. This means that these plants can only absorb water that comes into direct contact with it. For this reason, most nonvascular plants are primarily found in moist or rainy climates. Other species live directly in or near bodies of salt or fresh water, including many species of seaweed, kelp and most types of algae. Nonvascular plants are also unique in that they cannot produce seeds or flowers, unlike most vascular plants.