RESEARCH ARTICLE Comparison of Genetic Structure of Epixylic Liverwort Crossocalyx hellerianus between Central European and Fennoscandian Populations

Patterns of genetic variation and spatial genetic structure (SGS) were investigated in Cross-ocalyx hellerianus, a strictly epixylic dioicous liverwort (Scapaniaceae s.l., Marchantio-phyta). Studied populations were located in Fennoscandia and Central Europe, with localities differing in availability of substrate and the population connectivity, and their popu-lations consequently different in size, density, and prevailing reproductive mode. A set of nine polymorphic microsatellites was successfully developed and used. Identical individuals were only found within populations. Especially in large populations, the majority of the indi-viduals were genetically unique. Resampled number of genotypes, mean number of observed alleles per locus after rarefaction, and Nei’s gene diversity in large populations reached high values and ranged between 4.41–4.97, 3.13–4.45, and 0.94–0.99, respec-tively. On the contrary, the values in small populations were lower and ranged between 1.00–4.42, 1.00–2.73, and 0.00–0.95, respectively. As expected, large populations were found to be more genetically diverse than small populations but relatively big diversity of genotypes was also found in small populations. This indicated that even small population