XVI International Botanical Congess

To test hypotheses concerning the systematic position of the order Trentepohliales, nuclear and chloroplast gene sequences (SSU DNA and rbcL), were analyzed with distance, parsimony, and maximum likelihood approaches. Northern blot analyses were performed to elucidate the organization of the mtLSU rRNA. Studies were conducted with DAPI to quantify the nuclear DNA content. Our inferences on the phylogenetic relationship of Trentepohliales based on SSU and rbcL genes consistently place the Trentepohliales among the ulvophyceae. The continuous organization of the mtLSU rRNA genes is consistent with these results. Karyology and DAPI data suggest the hypothesis that evolution in the Trentepohliales has involved polyploidy. (Research supported in part by NSF grant DEB-9408057 to RLC and Sigma Xi Nat. grant to JMLB.)