There has been much discussion about infrageneric taxonomy of the genus Amaranthus. In the present study, in order to solve taxonomical problems and to aid identification of Iranian Amaranthus taxa, the palynological characteristics of seven taxa from two subgenera (Amaranthus and Albersia) were examined. Pollen grains were investigated with light microscopy and scanning electron microscopy using the prolonged acetolysis procedure. Twelve quantitative and qualitative characteristics were studied. Results showed that all of the studied taxa had poly pantoporate pollen and surface sculpturing was seen as scabrate, while its aggregation differed between samples. Statistical analysis showed that some quantitative morphological features were more valuable in identification of the studied taxa. The studied taxa were separated from each other using multivariate analysis. Our data together with the results of previous investigations confirmed that the present infraspecific classification of A. blitum requires change. It is advisable to return to the previous taxonomical status of the genus.
