The chromosome number ofT. ligusticumwas found to be 2n = 12, and that ofT. cherleri2n = 10. A comparison of the chromosomes of these species with those ofT. hirtum(2n=10) andT. 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.