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Key to Achillea

Asteraceae

Achillea

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1 Heads golden yellow
1 Heads white or pinkish.
  2 Leaves serrate to almost entire; ray laminae 4-5 mm long; phyllary margins brown; [section Ptarmica]
  2 Leaves pinnately dissected into linear segments; ray laminae 1.5-3 mm long; phyllary margins green or brown; [section Achillea]
    3 Fresh leaves elaborately 3-dimensional, the linear segments arrayed in a 3-D arrangement several millimeters “thick”; [common native]
    3 Fresh leaves essentially flat, the linear segments arrayed in a plane; [rare exotic]