Abstract: The chromosome numbers of three species of Aster L. from Southern Qinghai Province, are reported here for the first time; all of them were found to be diploids with 2n=18. Three species have the common characteristics of the resting nucleus of the complex chromcenter type and the prophase chromosome of the interstitial type. Found in three species are mainly similar median-and submedian-centromeric chro mosomes. A. yunnanensis Franch var. labrangensis displays three sat-chromsoms while A. diplostephioides displays two sat-chromsomes.

Key words: Aster L., Chromosome number, Karyomorphology