The Collaborative International Dictionary of English v.0.48:

Halophyte \Hal"o*phyte\ (h[a^]l"[-o]*f[imac]t), n. [Gr. "a`ls,
   "alo`s, salt + fyto`n a plant.] (Bot.)
   A plant found growing in salt marshes, or in the sea.
   [1913 Webster]

WordNet (r) 3.0 (2006):

halophyte
    n 1: plant growing naturally in very salty soil