Sea Purslane, a native species, has been added to the USWildflowers database (12/26/2011.) Scientific name is Sesuvium portulacastrum.  Photo below was taken at the Fort De Soto County Park  in Pinellas County, FL, on Dec 19, 2011. Go to the Sea Purslane detail page for more photos and information.

Sea Purslane, Sea Pickle, Shoreline Seapurslane – Sesuvium portulacastrum