Achillea genus --- Aster Subfamily 2.1 
common yarrow (Achillea millefolium) -- in August -- Arthur's Rock Trail, Lory State Park      white & cream
common yarrow (Achillea millefolium) -- in August -- Old Fall River Road, RMNP, CO            white & cream        CO-RMNP
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common yarrow (Achillea millefolium) -- in April -- Arapaho Bend Natural Area, Fort Collins, CO         FC-AB
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common yarrow (Achillea millefolium) -- in September -- Parvin Lake State Wildlife Area, CO