Stachys lavandulifolia grows wild in Iran and is claimed to be effective for the treatment of infection, asthma, inflammatory diseases, and especially rheumatism. Thus, four populations of this species were studied karyologically. The basic chromosome number, the ploidy level, the total length of the chromosomes, and five different measures of karyotype asymmetry were investigated. The basic chromosome number of the studied populations was obtained as x = 15. The presence of 60 chromosomes in all of populations corresponds to tetraploidy (2n = 4x = 60) levels. The size of mitotic chromosomes was small and the mean length varied from 1.30 to 1.48 lm. The smallest chromosomes were observed in Manbar population and the largest in Angoran population. In all of the populations, metacentric chromosomes were the most common, whereas sub-metacentric chromosomes were rare. Karyotypic indices obtained for all populations revealed that the karyotypes were slightly asymmetrical. The intrachromosomal asymmetry index (A1) index varied from 0.16 to 0.25, interchromosomal asymmetry index (A2) ranged between 0.05 and 0.14, and Paszko’s asymmetry index (AI) ranged from 0.08 to 0.44. Gachsar population showed the highest levels of karyotypic heterogeneity. Finally, the results of the present study are important for breeding programs and for understanding the taxonomic position of this species.
