Abstract
The hypothesis regarding the origin of Narcissus ×weickertii through hybridization of its putative parent species, N. papyraceus and N. gaditanus, is investigated in populations from the southwestern of the Iberian Peninsula. Multivariate analyses of quantitative morphological characters in both vegetative and flower structures, coupled with a descriptive analysis of qualitative traits, reveal that N. ×weickertii displays an intermediate morphology between its putative parents. Several anatomical traits of the leaf and scape provide additional support for its hybrid nature. Karyotype analyses show that N. ×weickertii has a 2n=21 karyotype, which falls between those of the putative parent species, with several chromosomes showing an inability to pair. Fluorescence in situ hybridization procedures, encompassing both FISH (targeting NOR regions) and GISH (using total DNA from the putative parents), yield conclusive evidence regarding the hybrid nature of N. ×weickertii and confirm the hypothesis about the identity of their putative parent species. Furthermore, phylogenetic relationships suggest that N. gaditanus likely served as the maternal parent, while N. papyraceus acted as the paternal species, maintaining the hybrid species the style polymorphism of their parent species. The degree of viability observed in the N. ×weickertii pollen grains might indicate that it could bear some possibilities of sexual reproduction beyond the typical vegetative propagation of many described Narcissus hybrid species.