Morphological variations of genus Alnus in Iran: assessment of five new taxa

The genus Alnus has two species in old references of the flora of Iran in which two varieties and one subspecies have been recorded. However, recently, five new taxa have been described and recorded for the flora of Iran. In this study, the herbarium samples were obtained during a widespread sampling from 25 stands, ranged from the most eastern limit of alder dispersion in Golestan to the west of Talish, across the plains and highlands of Hyrcanian forests. After sampling, 28 leaf and female cone morphological traits belonging to 140 alder individuals were measured and analyzed. The results of discriminant analysis showed 11 most important traits in differentiation of the taxa such as leaf angle in apex, blade shape at the base, type of serration, villosity intensity, presence of hairs on the upper surface of leaf and cone shape. In this analysis, 84.3% of recognized individuals were correctly grouped in the related taxon. The maximum disagreement between predicted and recognized groups corresponded to allocation of A. subcordata varieties to villosa and visc versa. Generally, the morphological traits of the two new species including A. dolichocarpa and A. djavanshirii were very similar to that of A. subcordata var. subcordata. While, three sub-species of A. glutinosa were distinguished by the same traits. Finally, the use of DNA barcoding techniques is suggested in order to verify the presence of new taxa in Iran.