Bryophytes have gained a lot of publicity in the past 10–15 years, at least among scientists. While there have always been those who for inexplicable reasons have had a particular fondness for bryophytes, in academic circles these organisms were generally viewed as just “poor relatives” of the more flashy and exciting angiosperms. The bryophytes include fewer species, of smaller stature, with more subdued colors, of less obvious ecological significance, and with apparently simpler and less exciting evolutionary stories to tell. That view has changed.

The three major groups of bryophytes – mosses, liverworts, and hornworts – comprise the earliest lineages of land plants derived from green algal ancestors. Although we still do not know with certainty which of the three lineages is the sister group to all other land plants, we do know that the earliest history of plants in terrestrial environments is inextricably bound to the history of bryophytes. If we wish to understand fundamental aspects of land plant structure and function, we should turn to the bryophytes for insights. These aspects include the origin and nature of three-dimensional plant growth from apical cells and meristems, the evolution of cellular mitotic mechanisms and machinery, the development of thick, water- and decomposition-resistant spore (and later pollen) walls, the molecular and biochemical mechanisms underlying desiccation tolerance, and plant genome structure, function, and evolution.