Blackmore and Barnes (1987) hypothesized that two factors contributed to evolution of the embryophyte spore wall; transfer of the sporopollenin wall from zygotes to meiospores, and the fusion of single lamina into multilaminate walls.
As an early diverging lineage of embryophytes, the liverwort clade is as old or older than any other land plant lineage (Mishler & Churchill, 1984; Hedderson et al.
spore walls: origin, development, and homologies.
Then, in the subsequent section, I will revisit the question of the origin of embryophyte life cycles from the perspective of our modern understanding of the phylogeny of embryophytes and their algal relatives.
The deepest dichotomy in the embryophyte clade appears to separate liverworts from other embryophytes, with hornworts the sister group of tracheophytes (Samigullin et al.
1987) recognize the Charophyceae as "Charophyta," a division distinct from Chlorophyta, perhaps more closely related to embryophyte plants (than other green algae).
Coleochaete indeed appears to offer developmental clues to embryophyte origins (Graham, 1984).
In chapter one, "Evolutionary significance of bryophytes," the authors build a firm comparative morphological case regarding bryophytes as embryophytes
along with the other terrestrial plants, the vascular plants.
dagger]) bryo- of mosses (Bryophytes start out Bruce Young as embryophytes
These two developmental processes have been described to occur in a broad spectrum of embryophytes
, from bryophytes to many flowering plant families.
New character, derived from life-cycle variations among embryophytes
Interpretation morphologique de l'embryon ches les Embryophytes
, avec application au cas des Graminees (Poaceae).