Glassworts
What are they?
East Anglia's coastal marshes would be pretty bare in many places if it wasn't for the vast colonies of glasswort strewn across the intertidal mud. These are the plants that are sold in bunches as 'samphire' along the coast and which are steamed or boiled and buttered in the same way as Asparagus. Glassworts are peculiar little plants that need a little understanding. Most are annual (we have one perennial species) and appear as fleshy green fingers in early summer. These fingers have scale-like sections, arranged in pairs and which are actually very reduced leaves. The leaves have narrowly membranous margins and are arranged in pairs that wrap around the stem. As the season develops, small florets appear along the stems, at first hidden beneath the scale-like tip of the leaves. These florets gradually appear either as a single floret or arranged in groups of three, the middle one larger than the outer ones. These florets are impressed into the stem so are easily overlooked unless the tiny yellow stamens or even tinier white stigmas are protruding.
Where are they found?
Glassworts occur almost exclusively in coastal, salt-laden habitats, where they are adapated to deal with the difficult growing conditions. Most species grow on intertidal mud with one or two venturing into mixed saltmarsh communities, wet puddles on coastal shingle and coastal hard standings of shingle or gravel.
Identification
Separating the various species of glasswort can be very difficult and is best left until late in the season (mid-September-October), as the autumnal colours of the various species can aid identification. Features to note include: the colour of the overall plant; the number of florets in a cluster (one or three); the precise arrangement of the florets (if more than one in a cluster); the precise shape of the tip of the scale-like leaf and the width of its membranous margin.
Purple Glasswort Salicornia ramosissima
Native. Widespread and common in a wide range of coastal, salt-laden habitats and the species most likely to be found in marginal habitats in shingle areas, and compressed soil near the coast. Flowers August to September. Often grows in abundance, forming extensive stands of plants that turn the saltmarsh purple in autumn. The scale-like leaves have a membranous margin of around 0.2mm in width and the point of the leaf has an inside angle of around 110 to 120 degrees.
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Shiny Glasswort Salicornia emerici
(Salicornia nitens) Native. Only recorded a handful of times in East Anglia but this is certainly down to lack of effort, though the species seems likely to be local and uncommon and doesn't form extensive colonies. Small numbers of plants may be found in the Blakeney to Wells area in Norfolk or along the River Ore in Suffolk. It grows in the middle and upper saltmarsh regions in open, muddy locations. Flowers August to September. Stems bright, shiny green, becoming orange- or buff-brown in autumn. The scale-like leaves have a narrow membranous margin and almost no point to the leaf, thus appearing almost as a horizontal line below the floret clusters. On the main stems, the lower fertile segments are less than 3mm long and less than 3.5mm wide at their narrowest point.
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Yellow Glasswort Salicornia fragilis
(Salicornia lutescens) Native. Only recorded a handful of times in East Anglia but this is certainly down to lack of effort, though the species seems likely to be local and uncommon. Small numbers of plants may be found in the Blakeney to Wells-next-the-sea area in Norfolk or along the River Ore in Suffolk. It grows in the lower saltmarsh regions in open, intertidal locations and often where the substrate is sandy. Flowers August to September. Stems typically become yellow-green in autumn. The scale-like leaves have a narrow membranous margin and almost no point to the leaf, thus appearing almost as a horizontal line below the floret clusters. On the main stems, the lower fertile segments are less than 3-6mm long and 3-6mm wide at their narrowest point. The main stems are usually relatively short and parallel-sided (compare with Long-spiked Glasswort) and typically have less than 12 floret clusters (though occasionally up to 15).
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Long-spiked Glasswort Salicornia dolichostachya
Native. Scarce but widely recorded in the lowest areas of muddy, intertidal saltmarsh. Locally common on the extensive, intertidal flats between Blakeney and Wells-next-the-sea. Flowers August to September. Stems typically become dull yellowish-brown in autumn. The scale-like leaves have a narrow membranous margin and almost no point to the leaf, thus appearing almost as a horizontal line below the floret clusters. On the main stems, the lower fertile segments are less than 3-6mm long and 3-6mm wide at their narrowest point. The main stems are usually relatively long and tapered (compare with Yellow Glasswort) and typically have more than 12 floret clusters.
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One-flowered Glasswort Salicornia disarticulata
(Salicornia pusilla) Native. Records show this species to be widespread on upper saltmarsh areas between Blakeney and Wells-next-the-sea and rare or absent elsewhere, but it has almost certainly been overlooked and may well be found elsewhere if searched for. Typically grows on drier saltmarsh, where the muddy marsh meets shingle or firmer ground where coastal grasses dominate. Flowers August to September. Stems typically become pinkish in autumn. The easiest glasswort to identify as the florets are borne singly, not in groups of three. Plants are usually many-branched with short branches.
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Perennial Glasswort Sarcocornia perennis
Native. Widespread in saltmarsh habitats and generally found where firmer sands or gravels underlie the mud and allow this perennial species to get established. Flowers July to October. As a perennial, this species forms solid mats of green stems, arising from creeping, woody bases. As well as the fertile stems that carry florets clustered in threes, plants have thinner, sterile stems that do not bear florets and often have arching tips.
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