Studies focused upon the evolutionary transition from ancestral green
algae to the earliest land plants are important from a range of ecolog
ical, molecular and evolutionary perspectives. A substantial suite of
ultrastructural, biochemical and molecular data supports the concept t
hat land plants (embryophytes) are monophyletically derived from an an
cestral charophycean alga. However, the details of phylogenetic branch
ing patterns linking extant charophytes and seedless embryophytes are
currently unclear. Moreover, the fossil record has so far been mute re
garding the algae-land plant transition. Nevertheless, an accurate ref
lection of major evolutionary events in the history of the earliest la
nd plants can be obtained by comparative paleontological-neontological
studies, and comparative molecular, cellular and developmental invest
igations of extant charophytes and bryophytes. This review focuses upo
n research progress toward understanding three clade-specific adaptati
ons that were important in the successful colonization of land by plan
ts: the histogenetic apical meristem, the matrotrophic embryo, and dec
ay-resistant cell wall polymers.