Chromosome count and karyotype of two species of Clematis (Ranunculaceae)

摘要

Karyotype morphometric data of two species of the genus Clematis L., a cosmopolitan and diverse genus, were studied. Clematis flammula is a diploid with 2n = 16 chromosomes. It exhibits a gradual decrease in size of chromosomes from 14.83 (±3.6) μm to 7.58 (±3.65) μm. Its karyotype formula (2n = 2x = 16 = 10m + 6sm) differs from those of Clematis orientalis (2n = 4x = 32 = 18m + 8sm + 6st), which is in addition a tetraploid species. The intrachromosomal asymmetry (A1) indicates that C. flammula had the most symmetric karyotype A1 = 0.39 in comparison to C. orientalis (A1 = 0.96). The karyological data available in the literature for the genus have also been discussed against the backdrop of the present analysis. This is the first attempt to present the karyotype morphometric data for the tetraploid cytotype of C. orientalis from India.