The Collaborative International Dictionary of English v.0.48:

Saltwort \Salt"wort`\, n. (Bot.)
   A name given to several plants which grow on the seashore, as
   the Batis maritima, and the glasswort. See Glasswort.
   [1913 Webster]

   Black saltwort, the sea milkwort.
      [1913 Webster]

WordNet (r) 3.0 (2006):

black saltwort
    n 1: a small fleshy herb common along North American seashores
         and in brackish marshes having pink or white flowers [syn:
         sea milkwort, sea trifoly, black saltwort, Glaux
         maritima]