A palynological study of the Lamiaceae in some habitats in Iran

Pollen grains of 33 species species belonging to 20 genera of the family Lamiaceae distributed in some habitats in Iran were studied using light and scanning electron microscope. For this purpose, pollen grains of Otostegia persica, Hymenocrater oxyodontus, and exine sculpture of three species, namely, Salvia splendens, S. hypoleuca, and Phlomis herba-venti subsp. lenkoranica were studied for the first time based on pollen morphology. The present study, therefore, showed considerable variation from very small, small, and medium to large size in pollen grains. In addition, the shapes varied from prolate-spheroidal, sub-prolate, sub-spheroidal, and sub-oblate to spheroidal in our study. The pollen grains colps observed into two different shapes i.e. tricolpate and hexacolpate, although octacolpate was observed in two species of Ziziphora clinopodioides and Z. tenuior. In the present study, 10 different exine ornamentation of pollen grains viz. micro-reticulate, reticulate, foveolate, foveolate-rugulose, foveolate-reticulate, bi-reticulate, rugolate-foveolate rugulose, regulate, and micro-foveolate-rugolate were also found. The present survey, therefore, indicateed that, pollen characters are valuable for taxonomic applications and may be a useful tool to differentiate variation between genera and species in the family Lamiaceae classification.