Karyomorphology of three endemic plants (Brassicaceae: Euclidieae and Arabideae) from the Qinghai-Tibet Plateau and its significance

In the paper, chromosome number and karyotype of three endemic genera from China are reported for the first time. Our results show that Anzhengxia yechengnica has a karyotype formula 2n = 2x = 14 = 6 m + 8sm and belongs to Stebbins-3A; Shangrilaia nana karyotype formula is 2n = 2x = 14 = 10 m + 4sm (2sat) and belongs to Stebbins-1A; Baimashania pulvinata karyotype formula is 2n = 2x = 16 = 12 m (2sat) + 4sm and belongs to Stebbins-1A. Anzhengxia and Shangrilaia are monospecific genera belonging to tribe Euclidieae and both have a basic chromosome x = 7. Baimashania, which belongs to tribe Arabideae, has two species which have a basic chromosome x = 8. The implications of these cytological data are compared with morphological support and the implications for each tribe are discussed. We also summarize chromosomal number variation and its systematic implications of two tribes from the Qinghai-Tibet Plateau.