It seems to me that although glassort (Salicornia dolichostachya) is a very simple name it reflects what must be quite a complex story. It is certainly a simple plant, basically just a green plant with no apparent flower, upright and branched, a bit like a small cactus I suppose. It starts green in May then turns yellowish before reaching reddish brown by September. It is plant found solely on saltmarsh and is very common at the western end of Poole harbour and it also occurs on tidal mudflats elsewhere in the county.
I cannot find much else to say about the plant itself other than it has a salty taste (from the sea water of course) and is used in salads in posh restaurants around here. In hope of more I turn to the Internet and, sure enough, there is stacks of information about this plant and its relatives. Its resistance to salinisation is being studied in some depth to see if it has genetic content that might help make crops salt resistant in other parts of the world where the soil is becoming more saline as the level sea rises. It is all very complicated but it is all there to read in papers if you are interested!
And glasswort must have some connection to glass? Sure enough, its ashes where used in the production of glass until the middle of the 19th century when better chemical formulae were created.