A taxonomic status of the Medicago rigidula was reviewed in Iran. Morphological characteristics and pollen grains were studied in 72 populations of this species collected from natural habitats were. The results showed that the populations of M. rigidula have three-pore or four-pore pollen grains. Three-pores populations had less coils of pod, long and hocked spine that correspond with the M. rigidula, but four-pores populations had more coils without spine or with tubercles or straight, short spine tip that correspond with the M. rigiduloides. Thus, both species M. rigidula (L.) All. and M. rigiduloides E. Small were distributed across Iran
