Study of Pollen Grains characters in the Genus Ranunculus L. (Ranunculaceae) from Iran

The genus Ranunculus L. is the largest genus in Ranunculaceae family. This genus has a wide distribution in the world especially in temperate zone. In this study the pollen grains were examined by light microscope and polar axis (P)، equatorial axis (E) and the P/E ratio were measured. Also they were studied by scanning electron microscope and the general shape in polar and equatorial view and exine sculpturing of pollen grains were determined. In present study pollen grains of annual species and three groups of perennial species، Radix rhizomatosa، Radix praemorsa and Radix grumosa were studied. It was found that the underground system character is an artificial and unappropriate trait in separating group. Thus as the groups Rhizomatosa and Praemorsa have various pollen and morphological similarities، they can be merged together.