Identification of hybrid formulae of a few willows (Salix) using ovule numbers

is a genus of considerable taxonomic complexity, and accurate identification of its species and hybrids is not always possible. Quantification of ovules was used in this study to verify the parentage of a few hybrids of . It has been shown that ovule numbers in willow hybrids are the mean of the ovule numbers of their parents. The ovule index of a prostrate specimen of affirmed that this was a hybrid of Salisb. and L., and the ovule index of the ornamental cultivar ‘The Hague’ affirmed that this was a hybrid of L. and Miq. Finally, we also examined a confusing group, previously identified in North America as . The ovule indexes and other morphological characters indicated that there were four taxa among the studied specimens: , , Fernald, and a hybrid of and that has not previously been described. It was concluded that quantification of ovules in willows is a reliable tool that can be used in willow taxonomy, genetics and population studies.