Bryophytes and the evolution of early land plants (Review)

Land plants arose from a common ancestor at least 470 million years ago and presently encompass four major lineages: liverworts, mosses, hornworts and tracheophytes. By integrating paleontological, morphological, developmental, genetic and phylogenetic data, Ligrone et al. reconstruct the divergence of these lineages and the evolution of fundamental land plant characters. They conclude that the last common ancestor of land plants was probably a leafless axial gametophyte bearing simple unisporangiate sporophytes, and suggest that since fundamental land plant characters primarily evolved in the bryophyte grade, the key to a better understanding of the early evolution of land plants is in bryophytes.