The chromosome numbers and karyotypes of Catharanthus, including C. roseus (L.) G. Don, C. roseus (L.) G. Don ‘Albus’ and C. roseus (L.) G. Don ‘Flavus’, were studied. The results showed that the irkaryotype formulae were all 2n=2x=16=2m+12sm+2T and their karyotypes were all “3A”. The chromosome numbers of their somatic cell were all 2n=16. But the disposed order of the terminal point chromosome and the median region chromosome were different in karyotype sequence among the species and two culvarieties.
