Source : Webster's Revised Unabridged Dictionary (1913)

Windflower \Wind"flow`er\, n. (Bot.)
   The anemone; -- so called because formerly supposed to open
   only when the wind was blowing. See {Anemone}.

Source : WordNet®

windflower
     n : any woodland plant of the genus Anemone grown for its
         beautiful flowers and whorls of dissected leaves [syn: {anemone}]