TAXONOMIC SIGNIFICANCE OF POLLEN an‎d SEED MICROMORPHOLOGY IN THE GENUS HESPERIS L. (BRASSICACEAE)

Genus Hesperis L. belongs to Brassicaceae (Cruciferae) family including 46 species in the world, of which seven taxa are distributed in Iran. Pollen and seed macro- and micromorphological features of the Iranian taxa belonging to three sections, including sects. Hesperis, Diaplictos and Pachycarpos were examined for the first time using light (LM) and scanning electron microscope (SEM). Data analyses were performed using PAST (ver. 3.14) software. The results showed that in Hesperis pollen grains are radially symmetrical, monad, isopolar, tricolpate and have a small size. Pollen grain shape is elliptic to circular in equatorial view and circular in polar view. The exine ornamentation is reticulate in all studied specimens. Seed sculpturing pattern revealed two main groups based on the presence or absence of papillae. This study clarified that both pollen and seed macro- and micromorphological characters are significant features in taxonomic classification of the genus Hesperis. Unweighted Pair Group Method with arithmetic mean (UPGMA) and Principle Component Analysis (PCA), strongly supported the sectional delimitation of taxa for most characters but not for seed qualitative characters. The results are mostly in agreement with the previous studies.