Abstract: The karyotypes of 4 species of Roegneria C. Koch are reported in this paper. The karyotypic formulae are as follows:R. sinica Keng, 2n=4x=28=28m(2SAT); R. nudiuscula L. B. Cai, 2n=4x=28=24m+4sm(2SAT); R. pendulina Nevski, 2n=4x=28=22m+6sm(2SAT); R. viridula Keng et S. L. Chen, 2n=4x=28=24m(2SAT)+4sm. The public and respective features of karyotypes of 4 species reflect the rationality of dividing species and coexisting in a genus in the morphological classification. Especially through the analyses of the karyotypic asymmetry and relative evolutive level, authors think that R. sinica Keng is the most primitive among the 4 species, R. viridula Keng et S. L. Chen is the most evolutive among them, while R. nudiuscula L. B. Cai and R. pendulina Nevski are intermediate in evolution; the Ser. Angustiglumes Nevski is more advanced than the Ser. pendulinae Nevski. The evolutive level shown by karyotypic asymmetry is related to the occurrence of the awn on glume among series, the elongation and thickening of the spike among species and the elongation of the awn on lemma among them.

Key words: Roegneria, Karyotype analysis, Evolution