Hybridization and introgression among threeAconitum(Ranunculaceae) species of different ploidy levels in the Tatra Mountains (Western Carpathians)

Hybridization among species of A conitum effects their morphology and ecology. In this study the hybridization between the diploid 2n( 2x ) = 16 ( A . lasiocarpum and A . variegatum ) and tetraploid 2n( 4x ) = 32 ( A . firmum ) species was documented in the T atra Mountains ( W estern C arpathians) in a small, local population in a semi‐natural site. The hybrid species were: homoploid A . × pawlowskii ( A . lasiocarpum × A . variegatum ), and triploid A . × berdaui ( A . firmum × A . variegatum , 2n( 3x ) = 24). Chloroplast DNA (cp DNA ) alleles formed two distinct haplotypes, one typical for the tetraploid and another for diploid lines, shared between the tetraploid, triploid and diploid groups, indicating introgressive hybridization. The presumed gene flow was from the tetraploid to diploid species via the triploid bridge. The only two specimens of A . × pawlowskii that harbored tetraploid ( A . firmum ) type cp DNA possessed bracteoles of A . firmum ‐type. The remaining introgressed (cp DNA and Inter Simple Sequence Repeats (ISSR) ) specimens ( A . variegatum ) were morphologically pure, implying cryptic introgression. ISSR loci shared between the tetraploid A . firmum and diploid A . variegatum support the hypothesis of an ancient allopolyploid origin of A . firmum and the diploid species of A . variegatum ‐type as one of its parent.