Source : Webster's Revised Unabridged Dictionary (1913)

Ragwort \Rag"wort`\, n. (Bot.)
   A name given to several species of the composite genus
   {Senecio}.

   Note: {Senecio aureus} is the golden ragwort of the United
         States: {S. elegans} is the purple ragwort of South
         Africa.

Source : WordNet®

Senecio aureus
     n : weedy herb of the eastern United States to Texas having
         golden-yellow flowers; sometimes becomes invasive;
         sometimes placed in genus Senecio [syn: {golden groundsel},
          {golden ragwort}, {Packera aurea}]