Source : Webster's Revised Unabridged Dictionary (1913)

Water starwort \Wa"ter star"wort`\
   See under {Starwort}.

Starwort \Star"wort`\, n. (Bot.)
   (a) Any plant of the genus {Aster}. See {Aster}.
   (b) A small plant of the genus {Stellaria}, having
       star-shaped flowers; star flower; chickweed. --Gray.

   {Water starwort}, an aquatic plant ({Callitriche verna})
      having some resemblance to chickweed.

   {Yellow starwort}, a plant of the genus {Inula}; elecampane.

Source : WordNet®

water starwort
     n : any of several aquatic plants having a star-shaped rosette
         of floating leaves; America, Europe and Asia