Source : Webster's Revised Unabridged Dictionary (1913)

Dayflower \Day"flow`er\ (-flou`[~e]r), n. (Bot.)
   A genus consisting mostly of tropical perennial herbs
   ({Commelina}), having ephemeral flowers.

Source : WordNet®

dayflower
     n : any plant of the family Commelinaceae [syn: {spiderwort}]