Symphytum tuberosum complex in central Europe: cytogeography, morphology, ecology and taxonomy.

The Symphytum tuberosum complex is a highly polyploid and taxonomically intriguing group. At least eight ploidy levels were recorded previously within this complex. Based on flow cytometric screening of 271 central-European populations, two dominant ploidy levels were revealed: tetraploid (2n = 4x = 32) and widespread dodecaploid (2n = 12x = 96). The tetraploid cytotype is mainly distributed along the southern and south-western margins of the West Carpathians where they abut the Pannonian basin, and found only in Slovakia, the Czech Republic (south-eastern Moravia) and Hungary; our findings represent the first records of this ploidy level for the latter two countries. In contrast, the dodecaploid cytotype occurs throughout the whole area studied. In addition to their geographic distributions, differences between the cytotypes in morphology and habitat requirements were detected using a multivariate morphometric analysis and analysis of a phytosociological database, respectively. Based on this information and taking certain overlaps in morphological traits and habitat requirements into account, we propose treating the dominant cytotypes as subspecies: S. tuberosum subsp. tuberosum (dodecaploids) and S. tuberosum subsp. angustifolium (tetraploids). In some populations, aneuploids and several minority ploidy levels were also detected, including DNA-hexaploids (only within populations of tetraploids), DNA decaploids and DNA-tetradecaploids (both only within populations of dodecaploids).