Pollen morphology has been extremely useful in clarifying systematic relationships within the plant taxa. Moreover, palynology of the species and subspecies could have taxonomic value as the supporting evidence to the morph ological and phylogenetic studies. Palynological studies of 12 collected Convolvulus populations from Markazi Province of Iran were done using light and scanning electron microscopy methods. PCA of obtained data was done using the SPSS. Results showed that there are wide variations in size of pollen grains, (min. in C. lineatus L. with P =38.40μm, E =37.80μm, P/E =1.01 and max. in C. commutatus Boiss. with P =54.00μm, E =56.70μm, P/E =0.95). The pollen shape, pollen type, exine ornamentation, length of the polar Axis ( P ) and length of the equatorial diameter ( E ), P/E , granule diameter and pore diameter are the most representative characters for separation of some Convolvulus taxa. Furthermore, P and E are more valuable in comparison with other pollen characters. Two exine ornamentation types and two pollen shapes were recognized confirming that the studied Convolvulus taxa are stenopalynous. The pollen grains are symmetrical, isopolar, monad, trizonocolpate and medium to large in size. The shape of the grains is oblate - spheroidal with the exception of C. lineatus (prolate - spheroidal). The exine ornamentation of grains is scabrate - punctate with the exception of C. lineatus (scabrate - punctate /fossulate). Since C. lineatus differs from other populations in size, P/E , shape and exine ornamentation, then it could be separated from the others. Finally identification key was prepared based on the studied palynological characters.
