Karyotypic studies in four species of Gynura in Tribe Senecioneae (Asteraceae)
Keywords:karyotype, Gynura pseudochina, G. procumbens, G. calciphila, Gynura sp.
Karyotypes of four Gynura species were investigated from root tips in mitotic metaphase. All species have the same chromosome numbers (2n = 2x = 20). Chromosome designations revealed that these species have the same symmetrical karyotype, consisting of metacentric (m) and submetacentric (sm) chromosomes. However, the differences in karyotype formulas of the four species were elucidated as follows: 7m + 3sm in two varieties of G. pseudochina DC., 8m + 2sm in G. procumbens Merr. and G. calciphila Kerr and 9m + 1sm in Gynura sp. These results show relationships among these four species.