Pollen morphology of some species of Amaranthaceae s. lat. common in Italy

Comparative studies on the pollen grains biometry and morphology of the most common species of Amaranthaceae s. lat. (incl. Chenopodiaceae) relieved in the Italian territory were carried out by Light Microscope and Scanning Electron Microscope in order to compare similarities and differences among them. Many pollen characters like diameter, volume, exine thickness, number of pores, pore density, interpore distance, pore size were considered and analyzed from statistical points of view. Fisher’s Least Significant Difference Test allowed clustering of groups and ordination analysis of taxa. Pollen analysis does not allow easy distinction of the pollen grains of the considered taxa. However, in spite of the many similarities shared by the two groups, some morphological and biometrical traits still allow the distinction of some taxa: interpore distance, exine thickness and above all microechinae density on pollen surface. These spinulous processes are more densely arranged on pollen from species of Amaranthus than from those formerly referred to Chenopodiaceae. The results obtained support the inclusion of the former Chenopodiaceae into Amaranthaceae.