TML> Vogel, Johannes*, Harald Schneider, Mary Gibby, Istvan Pinter, Steve Trewick, Mary Morgan-Richards, John Barrett, Stephen Russell, Sally Henderson, and Fred Rumsey. Phylogeographic methods have provided the opportunity to elucidate the effects of large-scale historical events (such as Pleistocene climate change) on the distribution and subdivision of biota and put in context the role of reproductive biology in the genetic structuring of species. A broad spectrum of organisms have provided grist to the phylogeographic mill including animal and various plant groups, but as yet there are few published studies of fern phylogeography. The phylogeny of the subgenus Ceterach (Aspleniaceae) was resolved by chloroplast DNA sequencing. Allozyme electrophoresis and cpDNA sequencing was employed to study diversity, distribution and prevailing breeding systems of the, mainly European, A. ceterach polyploid complex, comprising diploid, tetraploid and hexaploid taxa. We studied patterns of diversity within the known populations of diploid A. ceterach in Greece, the Balkans, Sicily and mainland Italy, located unreported diploid populations that might be alternative progenitors of colonising tetraploids, determine whether there have been multiple origins of polyploids, identified the origins of hexaploids, and mapped phylogeographic structure within and between ploidy levels with a view to further resolution of Pleistocene refugia in Europe. DNA sequences were obtained from c. 450 Asplenium ceterach plants representing 180 populations from throughout the range of the complex in Europe, plus outlying sites in North Africa, the near East and Asia. We identified nine distinct haplotypes from a 900 bp fragment of trnL-trnF gene. Patterns of haplotype diversity in diploid communities point towards evidence for the persistence of some populations in long term Mediterranean and a northern Pannonian-Balkan refugia, while haplotype diversity patterns in polyploid communities are either interpreted as the result of a rapid postglacial expansion or point towards secondary, Weichselian refugia in the western Mediterranean. Our cpDNA and ploidy data indicate at least six independent origins of polyploids, four among tetraploids and two amongst hexaploids.

Key words: Asplenium ceterach, chloroplast DNA, DNA sequence, multiple origins, Pleistocene, polyploidy, Pteridophyte