ibclogo XVI International Botanical Congess


Abstract Number: 3536
Session = 12.3.3


PHYLOGENY OF THE CHLOROPHYTA: THE CHLOROPHYCEAE AND TREBOUXIOPHYCEAE


M. Buchheim, University of Tulsa & L. Lewis, University of Connecticut


Motile cells of the Chlorophyceae and Trebouxiophyceae share a cruciate root system, but differ in basal body orientation (CW/DO vs. CCW). New 18S data place Eremosphaera Geminella and Microspora within the Trebouxiophyceae, however, their positions are not robust. Within the Chlorophyceae, 18S/28S data suggest that the Oedogoniales may be basal. Schizomeris and Aphanochaete are basal members of a monophyletic Chaetophorales. The flagellates are monophyletic. The Chaetopeltidales are monophyletic, but their position is not robust. Most DO taxa (e.g., Neochloris) are monophyletic. On the other hand, the Sphaeropleaceae (which have DO architecture) are highly divergent. As a consequence, the monophyly of all DO taxa is suspect. The existence of divergent lineages, not predicted by structure, indicates that further taxon sampling will expand our concept of the Chlorophyta.


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