XVI International Botanical Congess

Some of the most species rich and ecologically important genera in thebrown algae are contained in the fucalean families, Sargassaceae andCystoseiraceae. Recent molecular evidence from SSU data suggests a very close relationship between these two families calling into question the validity of their separate classification. Using sequence data from rbcL, rbcS, and IGS, the intra-and inter evolutionary relationships were evaluated. RbcL provides the best resolution of fucalean famial relationships whereas IGS is best suited for inter-to-intra specific inferences. Three of the 4 genera of the Sargassaceae were supported, whereas Hizikia was not. The data support a single family designation.