Source : Webster's Revised Unabridged Dictionary (1913)

Culver's physic \Cul"ver's phys"ic\, or Culver's root \Cul"ver's
root`\ [So called after a Dr. Culver, who used it.] (Bot.)
   The root of a handsome erect herb ({Leptandra, syn. Veronica,
   Virginica}) common in most moist woods of North America, used
   as an active cathartic and emetic; also, the plant itself.

Source : WordNet®

Culver's physic
     n : a tall perennial herb having spikes of small white or purple
         flowers; common in eastern North America [syn: {Culver's
         root}, {Culvers root}, {Culvers physic}, {whorlywort}, {Veronicastrum
         virginicum}]