1. Corollas yellow; leaves pinnatifid, with toothed segments.
1. Corollas white (or pink); leaves either finely dissected or merely toothed.
2. Leaves finely dissected; rays (1–) 1.2–3 mm long.
2. Leaves simple, linear-lanceolate, sharply and closely (but finely) toothed; rays ca. 4–6 mm long.
All species found in Achillea
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 19, 2018. https://www.michiganflora.net/genus.aspx?id=Achillea.