toothache grass
Webster's Dictionary (GCIDE)
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]