The Collaborative International Dictionary of English v.0.48:

Toadflax \Toad"flax`\, n. (Bot.)
   An herb (Linaria vulgaris) of the Figwort family, having
   narrow leaves and showy orange and yellow flowers; -- called
   also butter and eggs, flaxweed, and ramsted.
   [1913 Webster]

WordNet (r) 3.0 (2006):

toadflax
    n 1: common European perennial having showy yellow and orange
         flowers; a naturalized weed in North America [syn:
         toadflax, butter-and-eggs, wild snapdragon, devil's
         flax, Linaria vulgaris]