0STUDIES OF POLLEN GRAINS IN THE SECT. STENOCEPHALAE (COUSINIA CASS.-ASTERACEAE) IN IRAN

Pollen morphology of 25 species of section Stenocephalae Bunge from genus Cousinia Cass. is described and compared using Light and Scanning Electron Microscope. The pollen grains are prolate, isopolar, tricolporate and exine is densely or loosely verrucate. Based on morphological characters, species of this section can be divided to two groups: 1. species with narrow cylindrical heads and leathery leaves, 2. species with ovate heads and herbaceous leaves. The pollen grains of the first group with more than 20 verrucae and the second group with 3-30 verrucae in each 25 µm² of pollen surface are differentiated from each other. Indeed, these two detached grouping for species of sect. Stenocephalae are somewhat supporting each other.