Origin and distribution of polyploid Achillea (Compositae) in western North America
- Cite this article as:
- Tyrl, R.J. Brittonia (1975) 27: 187. doi:10.2307/2805480
The tetraploid and hexaploid cytotypes ofAchillea millefolium in western North America exhibit a complex distributional pattern involving overlapping ranges, mixed populations, and occasional pentaploid, septaploid, and octoploid plants. Cytogenetic and distributional evidence support the hypothesis that there has been a repeated autoploid origin of hexaploids from tetraploid progenitors. It is suggested that chromosome number differences should not be relied on as markers for infraspecific taxa in this complex.
Unable to display preview. Download preview PDF.