Abstract Background In the flowering plants. many polyploid species complexes display evolutionary radiation. This could be facilitated by gene flow between otherwise separate evolutionary lineages in contact zones. Achillea collina is a widespread tetraploid species within the Achillea millefolium polyploid complex (Asteraceae-Anthemideae). https://www.farmingtondepotgallery.com/product-category/swirl-decorations/