Pollen morphology of the genus Rubus L. subgenus Rubus (Rosaceae) in Iran

Pollen grains of 7 species of the genus Rubus L. were investigated using light microscopy (LM) and scanning electron microscopy (SEM). 14 different pollen characters were described, illustrated and compared in the present st-udy. All pollen grains were monad, tricolporate, radially symmetrical, isopolar, and medium in size. As for pollen sh-ape, 3 forms were recognized in the same specimens: prolate, perprolate and prolate-spheroidal. Endopore was located in the middle of colpi. The sculpture of the grains was confirmed to have striate pattern. The size of perforation and the orientation of the muri were compared and appeared to indicate the differences between the species. R.caesius, R. disc-olor, R. dolichocarpus and R. hirtus appear to have steriate-scabrate sculpture; in contrast, R. hyrcanus Juz., R. persicus Boiss. and R. sanctus Schreber. appear to have meandrical and fingerprint-like sculpture. Perforations are of two types. They are either large or often extending to tectal ridges or minute holes. Characters of pollen grains were proved their usefulness for separating taxa at the specific level. It seems that there is a link between the diversity of pollens and the vegetation habitats.