Green algae and the evolution of land plants: inferences from nuclear-encoded rRNA gene sequences.

Phylogenetic analysis of 381 informative sites in partial sequences of nuclear-encoded large and small subunit ribosomal RNAs from 38 chlorophyll a- and b-containing plants (Chlorobionta sensu Bremer) including tracheophytes, bryophytes, charophytes and chlorophytes, supports the hypotheses of: (1) monophyly of the green plants (excluding Euglenophyta); (2) monophyly of the embryophytes; (3) non-monophyly of the bryophytes; (4) monophyly of the tracheophytes; and (5) a single origin of embryophytes from charophycean green algae. The Charales and Klebsormidium appear to be the green algae most closely related to the land plants. The unexpected basal divergence of Coleochaete and the apparent non-monophyly of the Zygnematales are not robustly supported and, thus, are interpreted to be sources of new questions, rather than new phylogenetic hypotheses.