Abstract
The chromosome number of T. ligusticum was found to be 2n = 12, and that of T. cherleri 2n = 10. A comparison of the chromosomes of these species with those of T. hirtum (2n=10) and T. scabrum (2n = 10) showed that the karyotype of each species has distinctive features, but some chromosomes of the species with 2n = 10 are similar in size and shape and may be homologous. It is unlikely that T. ligusticum is ancestral to the other three species.