Molecular confirmation of Helosciadium × moorei (H. inundatum × H. nodiflorum; Apiaceae) from County Cork, Ireland

Helosciadium × moorei (Apiaceae), collected from County Cork, Ireland, is confirmed as an interspecific hybrid between H. inundatum and H. nodiflorum. The origin of this taxon was investigated using sequence data from a maternally inherited chloroplast marker (rps16-trnK), sequence data from a biparentally inherited nuclear marker (ITS), and fluorescent in situ hybridisation with labelled total genomic probes (GISH). The maternally inherited chloroplast marker identified H. inundatum as the seed-parent, the biparentally inherited nuclear marker identified contributions from two parental species, H. inundatum and H. nodiflorum, and GISH identified two parental genomes in H. × moorei (2n = 22): 11 chromosomes from H. inundatum and 11 chromosomes from H. nodiflorum. No evidence of recombination between parental genomes was detected in the hybrid, which strongly indicates that it is an F1. This definitive molecular and cytogenetic study unequivocally establishes the parentage of H. × moorei for the first time, and confirms the suspicions of generations of botanists.