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Abstract— Separate cladistic analyses of the green algae, liverworts, and hornworts are presented. Classificatory and evolutionary implications of these analyses, in addition to our previously published cladistic analyses of mosses and the embryophytes as a whole, are discussed. The embryophytes are monophyletic, and are part of a larger monophyletic group that includes some of the green algae (the “charophytes”). Important evolutionary transformations in the early phylogeny of the land plants include: (1) retention of the zygote on the haploid plant (gametophyte), with the sporophyte generation arising de novo by delaying meiosis, (2) independent elaboration of an elongate sporophyte in some liverworts, some hornworts, and in the moss‐tracheophyte clade, (3) independent origin of radial (axial) symmetry in the gametophyte in some liverworts and in the moss‐tracheophyte clade, (4) independent origin of leaves on the gametophyte in some liverworts and in mosses, and (5) the unique development of a branching sporophyte with multiple sporangia in the tracheophytes.

Interrelationships of major groups of green algae and land plants are currently hypothesized in cladograms by various authors. A summary cladogram is given and controversial points such as the precise sister group of the land plants are indicated. Sequence data from 5S ribosomal RNA are more homoplasious than morphological data and hence less useful for inferring phylogeny. Traditional textbook classifications contain several paraphyletic taxa and are frequently uninformative with respect to interrelationships/phylogeny. A cladistic classification with monophyletic taxa is advocated. It is superior for teaching purposes and provides natural taxa that are meaningful for biology in general.

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