Grasses: Arable Farmland & Disturbed Ground
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?
The grasses included on this page are the species most likely to be found on areas of regularly disturbed ground. This category covers huge areas of our region, since it includes arable farmland, which dominates the landscape throughout much of East Anglia. Arable land attracts a number of relatively short-lived annuals soon after cultivation, while land left fallow for a time will further be colonised by perennials such as the bents, Yorkshire-fog and Cock's-foot, with these forming a temporary sward until the land is next cultivated. Temporary disturbances to the land from other mechanical means - such as from gardening or disturbance from development projects - are also covered here and tend to attract a similar range of species.
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 (i.e. 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.
False Oat-grass Arrhenatherum elatius
A native perennial, common to abundant in many kinds of grassy places and often forming continuous cover for many miles along main roads and hedgebanks, from where it spreads into neighbouring open ground. Flowers June to August. Plants 50-180cm in height, loosely tussock-forming. Leaf blades 4-10mm wide, hairless or slightly hairy beneath, flat and pointed. Leaf sheaths rounded, usually smooth but sometimes a little hairy. Ligule membranous, short, rounded at the tip. Flower spike narrow when young, spreading at anthesis and becoming very narrow and upright with age. Spikelets 7-11mm with usually 2 florets (occasionally up to 5). Lower lemma with a 10-20mm awn, upper lemma shortly awned or awnless. Compare with other oat-grasses.
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Wild Oat Avena fatua
An ancient introduction from southern Europe. An annual of arable farmland found throughout East Anglia. Flowers June to September. Plants 30-150cm in height, loosely tussock-forming or stems solitary. Leaf blades 3-15mm wide, flat, rather rough and pointed. Leaf sheaths rounded, the lower ones often hairy. Ligule membranous, up to 6mm in length, rounded at the tip. Flower spike very open, with long side branches. Spikelets 18-30mm with 2-3 florets. Lemmas 14-20mm with a 2.5-4mm, bent and twisted awn arising from or near the middle of the back. A graceful grass, with the largest of grass flowers, making them useful for study when learning the flower parts of grasses. Compare with other oat-grasses.
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Yorkshire-fog Holcus lanatus
A native perennial, common to abundant in many kinds of grassy places and may become temporarily common in stubble fields between cultivations. Flowers May to September. Plants 20-100cm in height, variously as spaced stems or densely tussock-forming according to land use and management. Leaf blades 3-10mm wide, softly hairy or downy, flat and pointed. Leaf sheaths rounded, hairy. Ligule membranous, short to medium. Flower spike very narrow when young and typically pinkish-purple in colour, spreading at anthesis and remaining open with age. Spikelets 4-6mm with usually 2 florets. Lemmas keeled, the lower unawned, uppers shortly awned. Compare with other oat-grasses.
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Common Cock's-foot Dactylis glomerata
A native perennial, common to abundant in many kinds of grassy places and may become temporarily common in stubble fields between cultivations. Flowers June to September. Plants 15-140cm in height, typically densely tussock-forming. Leaf blades 2-14mm wide, greyish-green, coarse, folded at first but opening flat. Leaf sheaths strongly keeled (due to flattened stems), hairless but rough to the touch. Ligule membranous, medium to long. Flower spike consisting of one or two, well-spaced lower branches and a cluster of short branches at the top, the lower branches at right angles during anthesis and folding up with age. Spikelets 5-9mm with 2-5 florets, the spikelets tightly bunched in one-sided clusters. Lemmas tightly packed, elongated and sharp-pointed with a stiff awn. A very distinctive species once learned.
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Common Bent Agrostis capillaris
A native perennial found in most grassy places but especially on acid soils. Widely used as a grass for fine lawns and often spreading into nearby open ground. Flowers June to August. Plants 10-70cm in height and spreading by short rhizomes to form slightly tufted patches. Leaf blades 1-5mm wide, hairless, finely pointed at the tip. Leaf sheaths rounded, smooth. Leaf ligule membranous, long. Flower spike very narrow when young, open and spreading at anthesis and remaining open at fruiting. Spikelets tiny, 2-3.5mm, clustered towards the tips of very fine branchlets with a single floret in each spikelet. Lemmas not awned. Spikelets may be green (especially in shade) but are more often purplish. Compare with other bents.
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Creeping Bent Agrostis stolonifera
A native perennial, abundant in grassy places and readily spreading into nearby open ground. 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 membranous, 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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Black Bent Agrostis gigantea
A native perennial, widespread on arable field margins and occasionally on allotments and other disturbed areas. Flowers June to August. Plants 40-120cm in height, tufted and producing long, creeping rhizomes. Leaf blades 2-8mm wide, hairless, finely pointed at the tip, rolled when young but eventually flat. Leaf sheaths rounded, smooth or rough. Leaf ligule membranous, 1.5-12mm long. Flower spike narrow when young but soon open and spreading at anthesis. 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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Perennial Rye-grass Lolium perenne
A native perennial, abundant in most grassy habitats and readily spreading into neighbouring open ground. Flowers May to August. Plants 30-80cm in height, variably tussocky or more open and with non-flowering shoots (tillers) at flowering and fruiting time as well as creeping rhizomes. Leaf blades 2-6mm wide, hairless, slightly ridged on the upper side and distinctly glossy on the underside, folded along the midrib when emerging. Leaf sheaths rounded and hairless. Ligule membranous, short. Flower spike long, narrow and wiry. Spikelets 7-20mm with 4-14 florets, alternating from one side to the other along a sinuous central stem, with the flat face of the spikelets at 90 degrees to the central stem. Lemmas blunt or pointed at the tip, but without awns. Compare with other rye-grasses.
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Common Couch Elymus repens
A native perennial, common to abundant in a wide range of disturbed and open ground, roadsides and grassy places. Flowers May to August. Plants 30-120cm in height, variably tussocky or more often forming extensive patches from far-creeping rhizomes. Plants may be green or strongly glaucous (blue-grey). Leaf blades 1.5-10mm wide, hairless, slightly ridged and variably downy on the upper side and rough on the underside, the ridges having rounded (not flat) tops. Leaf sheaths rounded and hairless on the upper leaves, downy on the lower leaves, with the sheaths of the lower leaves not having a row of minute hairs along their exposed margin. Ligule membranous, very short. Flower spike upright or drooping to one side. Spikelets 10-20mm with 3-8 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, with or without an awn to 15mm in length. Largely replaced in coastal habitats by Sea Couch (Elymus athericus). Compare with other couches.
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Two-rowed Barley Hordeum distichon
An introduced annual, commonly grown as a crop and often appearing where it self-seeds from spilt grain along field margins and bare road margins. Flowers May to June. Plants 40-90cm in height, variably tussocky or more often producing single stems when not cultivated. Leaf blades broad, 14-15mm wide, hairless but rather rough. Leaf sheaths rounded with large, curving and overlapping auricles that wrap around the stem at the base of the leaf blade. Ligule membranous, short, with a blunt tip. Flower spike narrow, dense and upright. Spikelets in groups of three, the middle one fertile and stalkless, the outer two sterile and on short stalks. Glumes with awns 9-10mm long. Lemmas awned, those of the fertile spikelets being up to 12cm long. Compare with other barleys.
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Wall Barley Hordeum murinum
A native annual. Common to abundant in rough, disturbed or neglected ground and especially common in urban areas. Flowers May to August. Plants 6-60cm in height, often forming linear colonies along track sides and the foot of walls. Leaf blades 2-8mm wide, softly downy or smooth, rather limp and typically arching over. Leaf sheaths rounded, the lower ones hairy, the uppers hairless. Ligule membranous, very short and largely hidden by the winged auricles that wrap around the stem. Flower spike upright or slightly nodding, 4-12cm long. Spikelets each with a single floret, attached to each other in groups of three, the middle floret bisexual, the outer two male or sterile. Lemmas long and narrow, with a long awn 10-50mm in length. Compare with other barleys.
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Bread Wheat Triticum aestivum
An introduced annual, commonly grown as a crop and often appearing where it self-seeds from spilt grain along field margins and bare road margins. Flowers May to July. Plants 40-100cm in height, variably tussocky or more often producing single stems when not cultivated. Leaf blades broad, 6-16mm wide, hairless but rather rough on the margins. Leaf sheaths rounded with short, curving auricles at the base of the leaf blade. Ligule membranous, short, with a blunt tip. Flower spike narrow, dense and upright. Spikelets 10-15mm long with 3-6 florets. Glumes broad, unawned 9-10mm long, toothed at the tip. Lemmas typically unawned, but occasionally with an awn up to 16cm long. Compare with other barleys.
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Timothy Phleum pratense
A native perennial, common in natural and semi-natural grasslands and often found in stubble fields between crops. Flowers May to August. Plants 40-120cm in height, variably tussocky or forming patches. Leaf blades 3-9mm wide, hairless, rather stout. Leaf sheaths rounded and smooth. Ligule membranous, long, with a rounded tip. Flower spike narrow and upright. Spikelets 4-5mm long, each with a single floret, densely packed in the spike. The paired glumes are very distinctive and hide the lemmas and florets; they bear a comb-like line of stiff hairs along their edge and terminate in a pointed spike, 1-2mm long. Compare with other cat's-tails.
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Black-grass Alopecurus myosuroides
A native annual, found throughout most of our region and often abundant in cereal crops. Flowers May to August. Plants 20-80cm in height, variably tussocky or forming patches and often bent near the base. Leaf blades 2-8mm wide, hairless but rough textured. Leaf sheaths rounded and smooth, the uppers a little inflated. Ligule membranous, 2-5mm long, with a rounded tip. Flower spike slender and upright, 2-12cm long. Spikelets 4.5-7mm long, each with a single floret, densely packed in the spike. The paired glumes more or less cover the spikelets and are joined together at the base for up to half their length. Lemmas about as long as the glumes and bearing a short awn. Compare with other foxtails.
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Annual Meadow-grass Poa annua
A native annual or short-lived perennial found in all types of open ground, bare patches in lawns, gravel drives, cracks in walls and pavements etc. Flowers more or less throughout the year, but especially from late November to June. Leaves hairless, pointed at the tip or slightly rounded and hooded, 1-5mm wide. Flower spike open and spreading at anthesis and remaining open at fruiting. Spikelets densely packed with 3-10 florets. Plants in dry places can be very small and compact, but more open and spreading in shady or wetter places. Compare with other meadow-grasses.
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Red Fescue Festuca rubra
A native perennial, abundant in all kinds of grassy places. Flowers June to August. Very variable in appearance with several subspecies recognised, especially in coastal habitats. Plants 20-100cm in height and variably spreading or clump forming. Leaf blades often very fine, 1-5mm or more wide according to subspecies, hairless, finely pointed at the tip, rolled or flat. 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 5-14mm with 3-12 florets. Lemmas shortly awned. Compare with other fescues.
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Rat's-tail Fescue Vulpia myuros
A native annual, widespread in many kinds of open and disturbed habitats, especially on dry or sandy soils and as a weed in gardens and allotments. Flowers May to July. Plants 10-70cm in height, larger plants tussocky with many stems but single- or few-stemmed in drier sites. Leaf blades 0.5-3mm wide, flat or inrolled, downy above, smooth beneath. Leaf sheaths rounded and smooth. Ligule membranous, short to medium. Flower spike narrow and gracefully upright. Spikelets 7-10mm long, with 3-7 florets, loosely spaced in the spike. Lemmas 5-7mm long with a long and slender awn to 15mm in length. Compare with other fescues.
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Barren Brome Anisantha sterilis
A native annual, or overwintering as a biennial. Common to abundant in rough, disturbed or neglected ground, gardens and cultivated borders. Flowers May to July. Plants 15-100cm in height, very variable according to growing conditions. Leaf blades 2-7mm wide, coarse and shortly hairy, the blades typically spirally twisted. Leaf sheaths rounded and hairy. Ligule membranous, long and ragged-tipped. Flower spike consisting of long, slender branches, typically arching gracefully over to one side. Spikelets 40-60mm (including the very long awns) with 4-10 florets, the spikelets carried at the ends of the long branches. Lemmas strongly overlapping at first, later more open, with a long awn 15-30mm in length. Compare with other bromes.
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Great Brome Anisantha diandra
An introduced annual, which is perhaps more common in East Anglia than anywhere else in the country. A weed of arable land that commonly spreads into neighbouring hedgebanks and roadsides where the ground has been bared or disturbed. Flowers May to July. Plants 35-80cm in height, very variable but usually loosely tufted and often form large stands. Leaf blades 4-8mm wide, loosely hairy, rough. Leaf sheaths rounded and hairy. Ligule membranous, 3-6mm long and ragged-tipped. Flower spike consisting of long, slender branches, typically arching gracefully over to one side and with a roughly hairy central stem (rachis). Spikelets 70-90mm (including the very long awns) with 5-8 florets, the spikelets carried at the ends of the long branches. Lemmas strongly overlapping at first, later more open, with a long awn 35-65mm in length. Compare with other bromes.
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Common Soft-brome Bromus hordeaceus
A native annual, or overwintering as a biennial. Common to abundant in rough, disturbed or neglected ground as well as in open swards in grassy places. Flowers May to July. Plants 15-80cm in height, extremely variable according to growing conditions. Leaf blades 2-7mm wide, softly downy. Leaf sheaths rounded and hairy (often hairless on the uppermost sheaths). Ligule membranous, medium length and ragged-tipped. Flower spike upright at first, becoming more open at anthesis, then the branches closing together again later. Spikelets 12-22mm with 6-12 florets (really small plants may have just a single spikelet). Lemmas strongly overlapping, downy, with a short awn 5-10mm in length. The commonest form in a complex group of rather similar species and subspecies. Compare with other bromes.
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Common Cockspur-grass Echinochloa crus-galli
An introduced annual, frequently planted for pheasant cover on field margins or occurring from bird feeder spillage. Flowers August to October. Plants 30-120cm in height, forming loosely tufted clumps. Leaf blades broad, 10-20mm wide, with a pale midrib. Leaf sheaths keeled and smooth. Ligule absent. Flower spike upright at first, later strongly arching as the spikelets mature and with well spaced branches. Spikelets 3-4mm, globular and densely packed, with two florets - the lower male or sterile and the upper bisexual. Lemmas unawned, or lower lemmas with an awn up to 5cm in length. There are other, rather similar species that sometimes occur and which can be found on the page for millets.
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Green Bristle-grass Setaria viridis
An introduced annual, occasionally planted for pheasant cover on field margins or occurring from bird feeder spillage. Flowers August to October. Plants 10-60cm in height, forming loosely tufted clumps or solitary. Leaf blades 4-10mm wide, hairless. Leaf sheaths rounded, hairy on the margins. Ligule a fringe of silky hairs. Flower spike typically upright but may arch over in larger, mature specimens, 1-10cm long. Spikelets 2-2.5mm, globular and densely packed, with two florets; each spikelet accompanied by 1-3 bristles that bear tiny, forward-pointing barbs. There are other, rather similar species that sometimes occur and which can be found on the page for birdseed and cultivated aliens. Compare also with other bristle-grasses.
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Yellow Bristle-grass Setaria pumila
An introduced annual, occasionally planted for pheasant cover on field margins or occurring from bird feeder spillage. Flowers July to October. Plants 6-75cm in height, forming loosely tufted clumps or solitary. Leaf blades 6-10mm wide, hairless or hairy towards the base. Leaf sheaths rounded, hairy on the margins. Ligule a fringe of silky hairs. Flower spike upright, 1-15cm long. Spikelets 3-3.3mm, globular and densely packed, with 1-2 florets; each spikelet accompanied by 5-10, yellow bristles that bear tiny, forward-pointing barbs. There are other, rather similar species that sometimes occur and which can be found on the page for birdseed and cultivated aliens. Compare also with other bristle-grasses.
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