Liverworts (Marchantiophyta)

Abstract

Abstract The evolution of land plants marks one of the most important events in earth history. Because of their lengthy and well-documented fossil record, the major patterns in early land plant evolution have mainly been interpreted using macrofossil evidence from the vascular plant lineage (1). Liverworts (Fig. 1), in contrast, have a limited fossil record, they are easily neglected due to their small size, and their role in early land plant evolution is rarely emphasized. Nevertheless, growing evidence (1–7) indicates an early split in land plant evolution between the liverworts and all other land plants. this implies that liverworts occupy a critical position, and that they may help us understand the morphological and reproductive changes that favored the successful radiation of land plants and their adaptations to life in a terrestrial environment. Here we review recent progress in our understanding of phylogenetic relationships among major lineages and the origin and divergence times of those lineages.