WHAT ARE MOSSES?

Evolutionary stepping stones

Mosses are a category of plants. On one hand this may seem surprising because they do not have what we usually find in plants, like fruits, roots, or conspicuous stems and leaves. On the other hand, they are green like other plants and grow alongside them. However, it is important to note that not all ‘mosses’ are moss. Reindeer moss, Spanish moss, and Irish moss are actually not mosses (they are a lichen, a flowering plant, and an alga, respectively). 

Mosses, and their relatives hornworts and liverworts, are an important part in understanding the evolution of plants. All plants today: trees, grasses, moss, shrubs, and even cactuses evolved from a common ancestor of freshwater algae (like pond scum). Mosses, hornworts, and liverworts are important in this evolution because they have simpler structures that evolved earlier but stood the test of time compared to the more complex plants like trees.