| Chrysolaena flexuosa is a South American species of potential ornamental value (basic chromosome number of x=10). Diploid (n=10) and tetraploid (n=20) cytotypes have been reported for its distribution area, although one hexaploid (n=30-32ca.) cytotype has been reported for its most southern distribution. To investigate if ploidy and latitude are positively related in Ch. flexuosa natural populations and if sexual polyploidization could have had a role in the origin of the polyploid cytotypes, we determined chromosome numbers, DNA content, and pollen viability and size, and analyzed microsporogenesis in samples of seven Argentinian accessions. Two of the northeastern accessions were diploid and one was tetraploid, whereas the four southeastern accessions... |
