Liverworts on the Green Tree of Life Bryophytes as a natural
group Liverworts, along with mosses and hornworts, are often
referred to as “Bryophytes.” There is strong evidence, however,
that bryophytes, broadly defined in this way, are an artifical
(i.e., non-monophyletic) group. Instead, the three bryophytes
groups appear to form an evolutionary grade leading to the
tracheophytes or true vascular plants. The three bryophyte
groups (mosses, liverworts, hornworts) share a haploid-dominant
life and unbranched sporophytes, traits that appear to be
plesiotypic within the land plants (embryophytes). As early
diverging lineages of green plants, the bryophyte groups
comprise the oldest extant lineages of land plants. However,
which group of bryophytes was the first to diverge, taking hold
of terrestrial habitats for the first time? And which group is
most closely related to that most successful group of plants,
the vascular plants? Phylogenetic relationships among bryophyte
groups Identifying the earliest branch in