Chromosome numbers and polyploidy inLeontopodium(Asteraceae: Gnaphalieae) from the Qinghai-Tibet Plateau of S.W. China

Leontopodium R. Br. ex Cass. is the second largest genus within the Asian Gnaphalieae (Asteraceae) and is most diversified on the Qinghai-Tibet Plateau and its adjacent areas of SW China. The chromosome numbers and karyomorphology of five species from this region were investigated for the first time: Leontopodium sinense (2n = 28 = 22m + 6sm), L. muscoides (2n = 24 = 22m + 2sm), L. souliei (2n = 52 = 32m + 20sm), L. pusillum (2n = 72 = 52m + 20sm), and L. nanum (2n = 48 = 24m + 24sm). The results suggest that the basic chromosome number of Leontopodium is x = 14, followed with dysploidy numbers (e.g. x = 12, 13). Polyploidization has also played an important role in the evolution of Leontopodium in this region.