XVI International Botanical Congess

A cladistic analysis based on rbcL sequence data from a sample covering all major continents supports monophyly of two clades in Isoetes. One includes species from S. America (I. bradeii) and West Africa (I. kersii and I schweinfurtii) and the other clade includes species from all continents.These results stand in conflict with previous morphology based hypotheses concerning basal Isoetalean relationships. Furthermore, both major clades include species from several continents, implying that both groups were established before the final rifting of the Gondwana continent.Though higher level relationships remains unresolved, the results presented here provide important information on rooting options within the family for future analyses.