Karyomorphology of five taxa of Tanacetum sect. Xanthoglossa from Iran

In Flora Iranica area, Tanacetum comprised ۱۸ sections and ۵۴ species. Considering new findings, Tanacetum species in Iran has been increased to ۳۷. No detailed information on the karyotype analysis of the studied species was found in the literature. Therefore, in the present study, the detailed karyomorphology of six populations belonging to five taxa of Tanacetum sect. Xanthoglossa were studied. The basic chromosome number of the Tanacetum has been reported to be x=۹. Mitotic chromosome number of studied taxa were found to be diploid (۲n=۲x=۱۸) for T. argyrophyllum, T. oligocephalum (Khoy), T. uniflorum (no previous karyological records are known for this species) and T. pinnatum. According to the symmetry classes of Stebbins, class ۲A was found predominant karyotype class among the studied Tanacetum except for tetraploid (۲n=۴x=۳۶) T. polycephalum subsp. heterophyllum which was placed in ۲B. Karyotype analysis of each taxon has been presented and discussed.