The leaves could be mistaken for those of : Hottentot-Fig but they are much shorter and not solid but in-rolled.
Uniquely identifiable characteristics
Distinguishing Feature :
It is native and only grows near the sea.
The leaves are semi-succulent and are not as thick as what may first appear: for the edges are strongly in-rolled, like those of Bog Rosemary. It is the only plant in the Frankenia genus (at least in the UK). Sea Heath is quite rare and occurs only along some coasts near the sea on sandy or silty bareish ground or on the drier parts of saltmarshes. It occurs in the Channel Islands and in South East England, North Lincolnshire, and on Anglesey.
Species of Frankenia are another of those rare plants outside of the Fabaceae family (Legumes) which have the ability to fix nitrogen gas from the atmosphere. Other plants able to fix nitrogen are, Corncockle (Agrostemma githago),
Californian Cordgrass (Spartina foliosa) (which does not seem to occur in the UK), Sea-Buckthorn (Hippophae rhamnoides), Alder trees (species of Alnus), species of
Myrica such as Bog Myrtle (Myrica gale).
Some are only able to fix nitrogen with the aid of symbiotic organisms such as Frankenia (the only example in the UK being Sea Heath) and Water Fern (Azolla filiculoides) (via symbiotic organisms) and species of Gunnera (the so-called Giant-Rhubarbs).
There are other select plants capable of this feat, but most do not grow in the UK.