Grasses: Coastal Sites - Shingle Beaches & Saltmarsh
What are they?
This page aims to make the identification of grasses a little easier by bringing together the commoner species that are likely to be found in a particular habitat. This should help you to learn the more likely species that you will come across, though it should always be remembered that occasional individuals of other species may turn up in unexpected places from time to time.
Where are they found?
These species are found largely in coastal habitats and this page covers saltmarsh areas and shingle beaches. Extensive tracts of saltmarsh are found around The Wash, the North Norfolk Coast and along tidal sections of the main river estuaries from Great Yarmouth southward. Larger areas of shingle beach can be found from Blakeney Point to Cromer and along much of the Suffolk Coast. Rising gradients from these coastal habitats landward mean that there will typically be a gradual change into other habitats, especially into grass-dominated meadows, so this should be borne in mind if you find yourself along the higher, drier edge of saltmarsh, as other grasses may well creep in!
Identification
Identifying grasses successfully requires at least a basic knowledge of the plant parts and thus it's useful to know the names of these parts (it's much easier mentioning lemmas and glumes if one doesn't have to describe where they are every time!) To assist in this, you can click here to reference a page that gives details of these features. A good rule of thumb when working through the identification of any plant is to work from bottom to top with the whole plant and from outside to the middle with the flower parts (so - root, stem, leaf, flowers... sepal, petal, stamen, stigma) and this rule is generally followed here, though of course grass flowers have glumes, lemma, palea, stamens, stigma.
One important point to remember with grasses is that the flower spike can look very different according to how far along the process from flowering to setting seed that it is. Many species begin with a tight, rod-like cluster which opens out when in full flower and then closes back up again after pollination. Thus, it is important to look carefully at the parts of the florets (individual flowers) regardless of the shape of the overall flower spike, just to be sure. To get around this variability, botany books often write descriptions of grasses when they are said to be 'at anthesis'. This simply means at the point that the anthers open to release the pollen and this ensures that we are always looking at the flowers at the same point in their development. Grasses can still be identified outside of this point, but you need to understand that the overall spike might look different (the smaller flower parts will generally not change much, however). To simplify this a little, I have used the terms 'early flower spike/spikelets/florets' for spikes where the flowers have not yet reached anthesis; 'flowering spike' for plants at or around anthesis; 'late flower spike' for spikes where the flowers have passed anthesis and are progressing towards seed set. Where these terms are not used, you can assume that the flower spike doesn't change significantly in appearance over the course of the flowering period.
While this page contains the species that you are most likely to come across in most situations, it should be noted that most of them have look-alike, closely-related species. Therefore, it is recommended that you follow the link given for each species to the page where it will be compared in greater detail with possible confusion species, as a way of confirming your identification.
Common Saltmarsh-grass Puccinellia maritima
A native perennial which is often dominant in large tracts of mid- and upper-saltmarsh, generally being replaced by fescues on higher, drier ground. Flowers June to July. Plants up to 40cm in height but often much less, producing stolons and forming a creeping mat, often with Common Sea-lavender, Common Sea-purslane and Sea Aster. Leaves hairless, bluntly pointed and hooded at the tip, 1-3mm wide, often inrolled. Leaf ligule membranous, 1-3mm long, bluntly rounded. Flower spike stiff and wiry, open and spreading at anthesis and closing or remaining open at fruiting. Spikelets 5-13mm, densely packed with 3-10 florets. Glumes 1.5-4.2mm, unequal, lemmas 2.8-5mm long. The common grass of mid- and upper-saltmarsh areas, often forming a low, tight, turf or growing taller where competing with other grasses and sea-purslane along creek levees and higher ground.
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Reflexed Saltmarsh-grass Puccinellia distans
A native perennial found in a wide range of damp, salt-influenced habitats, including along the sides of inland roads where winter griting takes place. Flowers June to August. Plants up to 60cm in height, tufted and not producing stolons but typically in rather loose, open colonies of plants on more open ground. Leaves greyish-green, hairless, bluntly pointed and hooded at the tip, 1-3mm wide, not inrolled. Leaf ligule membranous, 1-2mm long, bluntly rounded. Flower spike stiff and wiry, open and spreading at anthesis and often with the lower branches reflexed (sometimes not). Spikelets 3-9mm, densely packed with 2-9 florets and clustered towards the tips of the branches. Glumes 0.7-2.8mm, unequal, lemmas 1.5-2.8mm long.
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Stiff Saltmarsh-grass Puccinellia rupestris
A tufted annual or biennial that grows on bare, seasonally damp ground on grazing marshes and the back of saltmarsh and shingle areas. Rare in East Anglia, with the main populations occurring southward from southeast Suffolk. Flowers May to August. Plants up to 40cm in height, tufted and not producing stolons. Leaves greyish-green, hairless, bluntly pointed and hooded at the tip, 2-6mm wide, not inrolled. Leaf ligule membranous, 1-2.5mm long, blunt to pointed. Flower spike stiff, often appearing one-sided, open and spreading at anthesis. Spikelets 5-9mm, densely packed with 3-5 florets on one side of the branches. Glumes 1.5-3mm, unequal, lemmas 2.8-4mm long.
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Borrer's Saltmarsh-grass Puccinellia fasciculata
A tufted perennial that grows on bare, seasonally damp ground on grazing marshes and the back of saltmarsh and shingle areas. Rare in East Anglia and nationally scarce, with the main populations occurring southward from southeast Suffolk. Flowers June to September. Plants up to 60cm in height, tufted and not producing stolons. Leaves greyish-green, hairless, bluntly pointed and hooded at the tip, 1.5-5mm wide, flat, or slightly folded upwards. Leaf ligule membranous, 1-2.5mm long, bluntly rounded. Flower spike stiff, with spikelets spaced along the branches (not clustered towards the tips). Spikelets 3-6mm, densely packed with 3-8 florets. Glumes 1-2.2mm, unequal, lemmas 1.7-2.3mm long.
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Common Cord-grass Sporobolus anglicus
(Spartina anglica) A native perennial of wet saltmarsh, typically occurring as a coloniser on bare mud or in saltmarsh pools. Flowers July to October. Plants 30-100cm in height, spreading by strong rhizomes to form often extensive colonies. Leaves greyish-green to bright green, hairless, sharply pointed at the tip, 6-15mm wide, flat or sometimes inrolled. Leaf ligule a ring of silky hairs, 1.8-3mm long, often visible from the side of the leaf base. Flower spike stiff and upright at anthesis with 2-12 branches. Spikelets 14-21mm, densely packed and overlapping with 1-2 florets and arranged in two rows pressed tightly against one side of the axis. Glumes keeled, pointed at the tip. Originated from a hybridisation event between an introduced species (S. alterniflorus) and our native Small Cord-grass near Southampton in about 1890. Since then, planted for coastal erosion protection and now widespread and common in suitable habitat throughout the British Isles.
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Small Cord-grass Sporobolus maritimus
(Spartina maritima) A native perennial of wet saltmarsh, typically occurring as a coloniser on bare mud or in saltmarsh pools. Once more common, now rather scarce and mostly found in muddy estuaries from Aldeburgh southward. Flowers July to October. Plants 15-50cm in height, spreading by strong rhizomes to form colonies. Leaves green or often purple-tinted, hairless, sharply pointed at the tip, 3.5-5mm wide, flat or sometimes inrolled. Leaf ligule a ring of silky hairs, 0.2-0.6mm long. Flower spike stiff and upright at anthesis with 1-5 branches. Spikelets 11-17mm, densely packed and overlapping with single florets and arranged in two rows pressed tightly against one side of the axis. Glumes keeled, pointed at the tip.
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Common Hard-grass Parapholis strigosa
A native annual of saltmarsh, particularly on compacted mud where saltmarsh meets sandy or gravelly substrate. More recently also along the margins of salted roads. Flowers June to August. Plants to 40cm in height, either solitary or in loose clusters. Leaves greyish-green to bright green, hairless, pointed at the tip, 1-2.5mm wide, flat or sometimes inrolled. Leaf ligule membranous, 1.8-3mm long, upper sheaths not inflated. Flower spike a narrow, stiff and upright or slightly curved, extension of the stem, 2-20cm in length. Spikelets 3-7mm, single-flowered and embedded in the stem, alternating from side to side. Glumes 3-7mm, stiff, pointed at the tip and neatly fitting over the hollow in the stem. Anthers 2mm long.
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Curved Hard-grass Parapholis incurva
An uncommon native annual of saltmarsh edge, particularly on compacted mud where saltmarsh meets sandy or gravelly substrate. Flowers June to July. Plants 2-20cm in height, either solitary or in loose clusters. Leaves green, hairless, pointed at the tip, 1-2mm wide, flat or sometimes inrolled, upper sheaths inflated. Leaf ligule membranous, 1.8-3mm long. Flower spike a narrow, stiff and slightly to strongly curved, extension of the stem, 1-8cm in length. Spikelets 4-6mm, single-flowered and embedded in the stem, alternating from side to side. Glumes 4-6mm, stiff, pointed at the tip and neatly fitting over the hollow in the stem. Anthers 0.5-1.5mm long.
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Saltmarsh Red Fescue Festuca rubra subsp. litoralis
A native perennial, very common in coastal habitats along creek levees and at the upper edge of saltmarsh, or where shingle underlies saltmarsh, giving a firmer substrate. Flowers June to August. Plants to 50cm in height with rather short rhizomes and forming dense colonies of stems. Leaf blades narrow, 1.2-2mm wide according to subspecies, hairless, finely pointed at the tip, typically folded. Leaf sheaths rounded, smooth, fused together more or less to the top and hiding the minuscule ligule. Flower spike spreading at anthesis, often slightly drooping towards the tip when young. Spikelets 8.7-11.2mm, upper glume 4.3-6.2mm, lemmas 5.7-8mm, shortly awned. Note that other forms of Red Fescue may occur, especially where saltmarsh or shingle interfaces with grazing marsh. Compare with other fescues.
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Sea Barley Hordeum marinum
A native annual. Nationally scarce and patchily distributed on upper-saltmarsh and along bare tracks in coastal grazing marshes and along raised floodbanks. Flowers June. Plants 10-40cm in height, typically forming small tufts without non-flowering shoots at flowering time. Leaf blades 2-6mm wide, lightly hairy or smooth. Leaf sheaths rounded, the lower ones hairy, the uppers hairless and with a short auricle. Ligule membranous, very short. Flower spike rather stiff and upright, 2-8cm long. Spikelets each with a single floret, attached to each other in groups of three, the larger middle floret bisexual, the smaller outer two male or sterile. Central florets with lemmas 6-8mm long and narrow, with an awn up to 24mm in length. Care should be taken in separating from Wall Barley, which can be common on floodbanks in some places. Compare with other barleys.
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Meadow Barley Hordeum secalinum
A native perennial. Widespread in our region in heavier soils, especially where prone to winter flooding, but especially frequent in coastal grazing marshes and along raised, coastal floodbanks, extending out into the upper-saltmarsh. Flowers June to July. Plants to 80cm in height, forming loose tufts with non-flowering shoots present at flowering time. Leaf blades 2-6mm wide, lightly hairy or smooth. Leaf sheaths rounded, the lower ones hairy, the uppers hairless and with a very short auricle or without auricles. Ligule membranous, very short. Flower spike upright but not stiffly so, 2-8cm long. Spikelets each with a single floret, attached to each other in groups of three, the larger middle floret bisexual, the smaller outer two male or sterile. Central florets with lemmas 6-9mm long and narrow, with an awn up to 12mm in length. Care should be taken in separating from Wall Barley, which can be common on floodbanks in some places. Compare with other barleys.
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Sea Couch Elymus athericus
A native perennial, common to abundant in a wide range of coastal grassy places, especially on coastal floodbanks and at the upper limit of saltmarsh habitat, where it can form extensive monocultures. Flowers June to August. Plants 30-120cm in height, forming extensive colonies and often laid over by the weather. Plants typically strongly glaucous (blue-grey). Leaf blades 2-6mm wide, hairless, slightly ridged on the upper side, the ridges having flat (not rounded) tops. Leaf sheaths rounded and hairless on the upper leaves, downy on the lower leaves, with the sheaths of the lower leaves having a row of minute hairs along their exposed margin. Ligule membranous, very short. Flower spike upright and rather stiff. Spikelets 10-20mm with 3-10 florets, alternating from one side to the other along a sinuous central stem, with the flat face of the spikelets facing the central stem, like clapping hands. Lemmas blunt or pointed at the tip, awnless, or sometimes with an awn to 10mm in length. Best told from Common Couch (Elymus repens) by the flat-topped leaf ridges and the minute bristles on the margin of the leaf sheaths. Compare with other couches.
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Lyme-grass Leymus arenarius
A native perennial, favouring sand dunes but also quite widespread on shingle and occasionally on low sea cliffs. Flowers July to August. Robust plants, growing to 150cm (sometimes more) in height, forming spreading clumps. Plants strongly glaucous (blue-grey). Leaf blades 8-20mm wide, ridged on the upper side, the ridges slightly rough. Leaf sheaths rounded and hairless. Ligule stiffly membranous, very short. Flower spike upright and rather stiff, 15-35cm in length. Spikelets 20-32mm with 3-6 florets, usually joined in pairs. Lemmas tough, pointed at the tip, awnless.
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Creeping Bent Agrostis stolonifera
A native perennial, abundant in grassy and wet places, especially on the interface between grazing marshes and saltmarsh. Flowers July to August. Plants 10-80cm in height and spreading by long, creeping stolons to form large, spreading patches. Leaf blades 0.5-5mm wide, hairless, finely pointed at the tip, rolled when young but eventually flat. Leaf sheaths rounded, smooth. Leaf ligule mebranous, medium to long. Flower spike very narrow when young, open and spreading at anthesis then closing again at fruiting. Spikelets tiny, 2-3mm, clustered towards the tips of very fine branchlets with a single floret in each spikelet. Lemmas not awned. Compare with other bents.
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Common Reed Phragmites australis
A native perennial, common to abundant in all kinds of damp places and often extending into shingle beaches and saltmarshes from nearby fresh or brackish areas. Flowers August to October. Plants 100-300cm in height with strong, creeping rhizomes that produce dense, single-species stands. Leaf blades 10-30mm wide, grey-green, hairless, flat and long-pointed. Leaf sheaths rounded, usually smooth, strongly overlapping around the stem. Ligule a line of long, white hairs. Flower spike narrow when young, spreading before anthesis and remaining open with age; a feathery panicle containing large numbers of spikelets. Spikelets 10-16mm, long and narrow, purplish and with 2-6 florets. Lemmas awnless but finely pointed.
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