Abstract The study investigates the genetic differentiation among two subspecies of Allium ursinum L., namely A. ursinum subsp. ursinum and subsp. ucrainicum as well as their putative hybrid that is represented by individuals with intermediate morphology. Inter-Simple Sequence Repeats (ISSR) were applied to determine the status of intermediate morphotypes in terms of their genetic pattern and to assess the level of genetic variability within and between various populations of A. ursinum. The study comprises 144 specimens from nine populations along the east-west transect in Poland, which includes localities of both subspecies and their putative hybrid. Among the examined populations, 48 bands were amplified, of which 45 were found to be polymorphic. The principal coordinate analysis (PCoA), the neighbour-net analysis and Mantel test showed a strong correlation between genetic variability and geographic distance. Analysis of molecular variance (AMOVA) revealed that a greater proportion of total genetic variation resided within populations rather than among them. The Structure Bayesian clustering analysis revealed the presence of three distinct genetic groups within studied populations, where ‘eastern’ genotypes correspond to A. ursinum subsp. ucrainicum, and ‘western’ to subsp. ursinum; whereas the third genetic group has the largest share in the individuals occurring at the border of the distribution ranges of both subspecies. The emergence of the third genetic group is probably an effect of hybridization events occurring within the secondary contact zone. Typical morphologically intermediate populations occur only in a relatively narrow geographical zone, but the hybrid zone revealed by molecular markers is actually much wider than it is suggested by the morphological pattern of individuals. The current distribution pattern of both subspecies of A. ursinum and their hybrid zone is related to the two main directions of postglacial migration of Fagus sylvatica to the area of Poland. The hybrid zone arose as an effect of the secondary contact of two divergent lineages of A. ursinum.

Abstract This study deals with populations of the European-South-Siberian geoelement Adenophora liliifolia (L.) A. DC. in the Czech Republic, Slovakia, Hungary, Romania, and Poland, where this species has its European periphery distribution. We studied the population size, genetic variability, site conditions, and vegetation units in which A. liliifolia grows. Recent and historical localities of A. liliifolia were ranked into six vegetation units of both forest and non-forest character. A phytosociological survey showed differences in the species composition among localities. Only a weak pattern of population structure was observed (only 22% of total genetic variation present at the interpopulation level, AMOVA analysis), with moderate values for gene diversity (Hj = 0.141) and polymorphism (P = 27.6%). Neighbor-joining and Bayesian clusterings suggest a similar genetic background for most of the populations from Slovakia, the Czech Republic, and Poland, contrary to the populations from Hungary, Romania, as well as two populations from Central and South Slovakia. This might be explained by a relatively recent fragmentation of the A. liliifolia populations in Central Europe. Nevertheless, it seems that several populations in Romania, South Hungary, and Slovakia were isolated for a longer period of time and their genetic differentiation is more evident.