XVI International Botanical Congess

Morphological, biochemical, and molecular characters support the specific relationship of the land plants to the Charophyte algae. However, the Charophytes are paraphyletic according to most molecular phylogenies. The 4.5S rRNA gene, ubiquitous in land plants, arose before the divergence of some or all Charophytes. Chara australis, a complex Charophyte, is known to possess a 4.5S gene, but this has not been determined for the other Charophyte lineages. The presence or absence of this gene should have great utility in phylogenetic analysis to clarify the relationships among this large group of organisms. Representatives of each of the five orders of Charophyte class (sensu Mattox and Stewart) have been included in the present study. The region of interest has been amplified by PCR. Sequence alignments show the presence or absence of a putative intergenic spacer. RNase protections, and/or primer extensions will verify the presence or absence of the 4.5S rRNA, which is approximately 100 nucleotides in length.