Taxonomic evaluation of the tetraploid populations of Cardamine amara (Brassicaceae) from the Eastern Alps and adjacent areas

Abstract

Tetraploid populations of C. amara occupying the area of the Eastern Alps and neighbouring areas are described as a new subspecies, C. amara subsp. austriaca Marhold. The distribution area of these populations largely coincides with the area heavily affected by Pleistocene glaciation and it is suggested that the polyploidization event or events occurred during interglacial or early postglacial periods. Morphometric analysis of diploid and tetraploid populations of C. amara revealed that the new subspecies is morphologically close to diploid C. amara subsp. amara, but it can be separated from this taxon by the combination of several morphological characters from among of which the size of pollen grains is the most important.