Achillea ptarmica L., Sp. Pl. 2: 898 (1753).
Sneezeweed or sneezewort flower stalks appear as tiny white daisies with cream to brown centers on ribbed stalks. Heads are 7-10 mm across with 6-15 white rays. The double-flowered forms do not seem to be used in potpourri.
Achillea ptarmica is native to Europe but widely cultivated worldwide in temperate climates.
Asteraceae
Achillea speciosa Henkel