Thirty-six images of Yarrow, Achillea millefolum grows throughout temperate and boreal regions of the Northern Hemisphere and to some extent in the Southern Hemisphere. It is a hardy, highly variable aromatic perennial. Yarrow has been used to stop bleeding and heal wounds by cultures from the ancient Greeks to North American Indians. Over 120 compounds have been found in yarrow and it has a complex and variable essential oil. At least fourteen different chemical races have been identified in Europe. In addition to genetic variation affecting chemical content, the habitat, climate and geology in which the plant occurs can also effect the quality of the chemical content.