Abstract: Nitraria L. is a widespread genus of some 13 species from Africa, Asia, Europe and Australia. Taxonomic relationships of the genus have been subject to a wide diversity of opinion. Based on the number of chromosome, and combined with morphological and geobiological data of 13 species in genus Nitraria L., they were divided into two groups: diploid group (2n=2X=24) and tetraploid group (2n=4X=48). Polyploidy (2X→4X) is a basic evolutionary trend in the diversification of plants in genus Nitraria L.. A possible original site of the genus Nitraria L. was the coast of ancient Mediterranean. The central Asian and the northwestern China are its modern center of distribution. A applied perspective for molecular ecology research on these desert plant species was also suggested.