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):

saltwort
    n 1: bushy plant of Old World salt marshes and sea beaches
         having prickly leaves; burned to produce a crude soda ash
         [syn: saltwort, barilla, glasswort, kali,
         kelpwort, Salsola kali, Salsola soda]
    2: low-growing strong-smelling coastal shrub of warm parts of
       the New World having unisexual flowers in conelike spikes and
       thick succulent leaves [syn: saltwort, Batis maritima]