ctenium americanum

from The Collaborative International Dictionary of English v.0.48

Toothache \Tooth"ache`\, n. (Med.)
   Pain in a tooth or in the teeth; odontalgia.
   [1913 Webster]

   {Toothache grass} (Bot.), a kind of grass ({Ctenium
      Americanum}) having a very pungent taste.

   {Toothache tree}. (Bot.)
   (a) The prickly ash.
   (b) A shrub of the genus {Aralia} ({Aralia spinosa}).
       [1913 Webster]