Source : Webster's Revised Unabridged Dictionary (1913)

Wormseed \Worm"seed`\, n. (Bot.)
   Any one of several plants, as {Artemisia santonica}, and
   {Chenopodium anthelminticum}, whose seeds have the property
   of expelling worms from the stomach and intestines.

   {Wormseed mustard}, a slender, cruciferous plant ({Erysinum
      cheiranthoides}) having small lanceolate leaves.