Karyotypes are studied in eight species and two subspecies of Japanese Saussurea. All of the species examined have 26-chromosomes in diploid condition, but two of them have B-chromosomes which vary between 2 and 12 in number. The largest chromosome is about 5 μ in length and the smallest about 2 μ. The thirteen pairs of chromosomes at mitosis in the root tip are usually observed in all the species investigated. The large and the small four pairs of chromosomes can be easily distinguished from the other nine pairs of chromosomes which vary gradually in size. The first pair has median centromere and the second pair submedian, while the thirteenth pair has terminal centromere. Difference of the karyotypes in each species is observed in the other ten pairs of chromosomes. S. amabilis has four pairs of median chromosomes, while S. gracilis and S. ussuriensis have three pairs of submedian chromosomes. S. triptera has five pairs of subterminal chromosomes, while S. nipponica subsp. sendaica has six pairs of terminal chromosomes. Considering the karyotypes of these species examined, S. amabilis is different from the other species. Similarity of the karyotypes is found in both S. gracilis and S. ussuriensis, and in both S. sinuatides and S. nipponica subsp. savatieri, respectively. On the other hand, difference of them is observed in the subspecies of S. nipponica : subsp. sendica and savatieri.
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