I always buy samphire when the fishmonger has it. I love the salty taste and it counteracts the over-richness of fried salmon so well. When fresh, green and moist it conjures images of ocean and coast; somehow it brings me closer to nature.
Salicornia quinqueflora growing on rocks just above the high-tide line at Low Head near George Town in Tasmania. Note the tendency to form a clump and also see the old stems from previous years. Photo: John Grace
We have often come across Salicornia during our visits to Australia’s coastline, looking much like the Salicornia we find growing on salt-marsh in Britain, with the same salty-crunchy taste. At first I thought it was indeed our own Salicornia europaea (as so many European species are thriving in Australia). But after a little research I realised this one was the native Australian species Sarcocornia quinqueflora. A little more research revealed that taxonomic analysis using the tools of molecular genetics has suggested that all the world’s Sarcocornia species, including Sarcocornia quinqueflora, should be put into Salicornia. This new name for the Australian version of glasswort, Salicornia quinqueflora, is now enshrined on Kew’s Plants of the World On-line.
Contrasting growth forms of the perennial S. quinqueflora and the annual S. europaea. Photo credit are: left, John Grace at Cloudy Bay, Tasmania; right, Chris Jeffree at Tyninghame, Scotland.
Salicornia has been considered a difficult genus for taxonomists, as the leaves are almost non-existent and the flowers are much-reduced and hidden, so there are rather few characters for identification. One crucial difference between Salicornia and (the old) Sarcocornia is the life cycle. All Salicornia species are annual plants whereas Sarcocornia is a perennial, with older stems becoming woody and somewhat trailing. I’ve now seen Sarcocornia in about a dozen locations in Australia, and mostly it has been living on rocky shores. It can grow on the flood plains of brackish estuaries too, but I haven’t seen it forming a continuous green sward as our own Salicornia europaea does on salt marshes. Perhaps someone from Australia reading this would like to make further comment on the habitat preferences. It isn’t always coastal: I have read that extensive inland communities have developed on salty areas in Otago, New Zealand, where the plant is also native.
Left: S. quinqueflora forming more-or-less permanent clumps and stabilizing the shingle at Bruny Island, Tasmania (photo: John Grace) and Right: a sward of the annual S. europaea at Aberlady Bay, Scotland (photo: Chris Jeffree).
The structure of all Salicornia species is most unusual. The stem is segmented and the opposite leaves are tiny (a few millimetres), triangular, with knobbly petioles. The surface of the plant is glossy, presumably to allow sea water to run off. The lack of proper leaves must reduce light interception and photosynthesis of the plant as a whole (as in many desert and coastal plants) but the relatively low surface area to volume presumably reduces water loss and protects against the powerful scouring action of wind-blown sand.
Seedlings of S. europaea arising from seeds which have germinated in the cracks that developed in the substrate during a dry spell, at Tyninghame (Scotland). Image: Chris Jeffree.
The rates of photosynthesis of Salicornia are low by the standards of other C3 species (less than 20 micromoles CO2 m-2 s-1), and the stomatal density is low also. However, the growth rate can be rather high in optimal conditions (Pearcy & Ustin 1984). What is surprising is that Salicornia does not merely tolerate saline conditions, but it grows better when given quite strongly saline growth media (Pearcy & Ustin 1984, Davy et al 2001). It is therefore a good example of an extreme halophyte.
Female (left) and male (right) flowers of S. quinqueflora. Plants may be monoecious or dioecious (see this article). Attribution: Kevin Thiele from Perth, Australia, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons.
Salicornia belongs to the Amaranthaceae, the family of beetroot, spinach, quinoa and orache. Many in this family tend to develop red coloration due to the accumulation of an amino acid called betaine, first isolated many years ago from sugar beet. This acts as an osmoticum, enabling the cells to take up water whilst not interfering with metabolism.
Distribution of S. quinqueflora (upper) and S. europaea agg. (lower). S. quinqueflora has not been reported outside Australasia. From GBIF, the Global Biodiversity Information Facility.
Salicornias have been collected for food since ancient times. Researchers have considered it as a future food crop, especially in regions where fresh water for irrigation is scarce (Ventura and Sagi 2013). It should be possible to develop seawater agriculture by selective breeding from wild collections of Salicornia, especially given the diverse genetic base within the genus, just as modern crops were developed from wild ancestors. This might be combined with established marine farming (mussels, oysters, salmon).
In former times Salicornia was sometimes used in glass-making to make ‘soda-glass’. Burning the plant material to form ash results in a powder which is rich in sodium carbonate. In Scotland there was an industry based on soda ash, which could be derived from Kelp or from Salicornia. The name Salicornia comes from the Latin sal (‘salt’) and cornu (‘horn’).
Australian names for the plant include: beaded samphire, bead weed, beaded glasswort and simply glasswort.
References
Davy AJ, Bishop GF and Costa CSB (2001) Salicornia L. (Salicornia pusilla J. Woods, S. ramosissima J. Woods, S. europaea L., S. obscura P.W. Ball & Tutin, S. nitens P.W. Ball & Tutin, S. fragilis P.W. Ball & Tutin and S. dolichostachya Moss). Journal of Ecology 89, 681-707. https://doi.org/10.1046/j.0022-0477.2001.00607.x
Guy RD, Reid DM & Krouse HR (1986) Factors affecting 13C/12C ratios of inland halophytes. II. Ecophysiological interpretations of patterns in the field. Canadian Journal of Botany, 64, 2700–2707,
Pearcy RW & Ustin SL (1984) Effects of salinity on growth and photosynthesis of three California tidal marsh species. Oecologia 62, 68-73.
Piirainen M, Liebisch O & Kadereit G (2017). “Phylogeny, biogeography, systematics and taxonomy of Salicornioideae (Amaranthaceae/Chenopodiaceae) – A cosmopolitan, highly specialized hygrohalophyte lineage dating back to the Oligocene”. Taxon 66,109–132. doi:10.12705/661.6.
Ventura Y, Sagi M (2013) Halophyte crop cultivation: The case for Salicornia and Sarcocornia. Environmental and Experimental Botany 92, 144-153.
©John Grace
Botany in Scotland 