Saltwort

We believe this little succulent plant, found not far from our home near the edge of a mixed marsh-black mangrove stand on the Cedar Keys, to be saltwort. Like glasswort, it is adapted for an environment in which fresh water is a rare, but essential commodity. There are two wetland plants called "saltwort," but this one (Batis maritima) is easily distinguished from the other (Salsola kali), which is a prickly plant frequently referred to as Russian thistle. 
(See my comment below).

The observation platform is frequently awash

Our recent visit coincided with a new moon and very low tide, making it appear that getting our feet only a bit wet we could walk from Cemetery Point on Way Key all the way to Haven Island, or from Sandspit Point all the way to Atsena Otie.