Constant species

Cymbalaria muralis.

Physiognomy

The Cymbalarietum muralis comprises often very open and fragmentary crevice vegetation in which little hanging clumps of Cymbalaria muralis are the most obvious feature. Indeed, Cymbalaria is the only frequent vascular plant in this community. There can be occasional scattered rosettes of small ferns – Asplenium trichomanes, A. ruta-muraria and Polypodium vulgare – together with patches of Sedum acre, short trails of Hedera helix, isolated tufts of grasses like Poa annua, Dactylis glomerata, Agrostis capillaris and A. stolonifera and some ephemeral herbs but the consistency and cover of such contributions are never high.

More frequent as a group are mosses with small patches of Homalothecium sericeum and tufts of Schistidium apocarpum, Grimmia pulvinata, Tortula muralis, Bryum capillare and Barbula unguiculata occasional to common in the crevices.

Habitat

The Cymbalarietum is characteristic of sunny crevices among the stone- and brick-work of boundary walls and buildings throughout the lowlands of Britain.

Zonation and succession

The Cymbalarietum can be found with other kinds of crevice vegetation where walls have been colonised by different mixtures of species tolerant of the extreme conditions of the habitat. In the warmer south and east of Britain, the Cymbalarietum can be found with the Parietarietum where Parietaria diffusa is the distinctive dominant among the crevices, and Segal (1969) saw this as sometimes a successional replacement for the Cymbalarietum.

Synonymy

The Puccinellietum maritimae includes a considerable range of closely-related vegetation types. The limits of the association as a whole are similar to those adopted in recent Continental accounts (e.g. Beeftink 1965, Westhoff & den Held 1969) and, as such, would include all or part of a variety of salt-marsh types in earlier British descriptions. The synonmy of the communities is complex and, as many synonyms would be partial, a complete list is not attempted here. Where a particular sub-community has a clear counterpart in litt. a note is given below.

Constant species

Puccinellia maritima.

Rare species

The association does not provide the sole, or even major, context for any national rarity but the following occur occasionally: Arthrocnemum perenne, Limonium bellidifolium, L. binervosum, Salicornia pusilla, Spartina maritima and Suaeda vera.

Physiognomy

Mostly, the association occurs as a closed species-poor grassland but the complete range includes very open pioneer vegetation and herb-dominated stands in which Puccinellia maritima is of minor importance or even absent. The sward varies from a tight low turf 1–2 cm high to a rank mattress up to 50 cm tall. Although grazing is important in controlling the physiognomy (see below), a considerable range of genetically determined morphotypes of P. maritima is present in Britain (Gray & Scott 1977a; 1980).

Inula crithmoides is a maritime perennial largely confined to southern England and Wales: it is recorded from Essex round to Anglesey with an isolated station in south-west Scotland (Perring & Walters 1962). Although it occurs in maritime cliff communities throughout its range, occurrences in salt-marsh vegetation are restricted to south-east England from Essex to Hampshire.

Here it is an occasional in various associations but it is sometimes encountered in abundance, usually with Halimione portulacoides as a co-dominant. In the few available samples there is a distinction between stands where Puccinellia maritima, annual Salicornia spp. and Limonium cf. vulgare are constant in generally small amounts and those which have abundant Elymus pycnanthus. The former occur on low-marsh sites with coarse sand; the latter on moderately organic soils with much drift litter on the upper marsh.

Ranwell (1972; Ranwell & Boorman 1977) has correlated the distribution of I. crithmoides on salt-marshes with the occurrence of lime-rich freshwater influence and the presence of Chalk bedrock near the surface. Though this may be true, it is difficult to see the ecological significance of the observation: most salt-marshes are alkaline to some degree and I. crithmoides may be climatically restricted to salt-marshes which are coincidentally particularly base-rich.

Within its limited range on salt-marshes, I. crithmoides tends to be more confined to high-marsh occurrences with Elymus pycnanthus in Essex (see Rose 1964, Rose & Géhu 1964).

Constant species

Agrostis stolonifera, Glyceria maxima, Myosotis scorpioides, Ranunculus sceleratus, Rorippa islandica.

Physiognomy

The Ranunculetum scelerati includes open or closed carpets of vegetation, locally lush, in which mixtures of Myosotis scorpioides, Ranunculus sceleratus, Rorippa islandica and Agrostis stolonifera occur, often among scattered shoots of Glyceria maxima. Veronica catenata, V. beccabunga, Nasturtium officinale agg. and Berula erecta are occasional to frequent and there are sometimes small tussocks of Deschampsia cespitosa, Holcus lanatus, Juncus inflexus and J. effusus. Small patches of Lemna gibba or Callitriche stagnalis can occur scattered on wet mud or shallow pools among the vegetation. Typically, Bidens tripartita and knotweeds are, at most, occasional.

Habitat

This is a community of very nitrogen-rich, intermittently wetted and disturbed ground such as the heavily-manured surrounds of ponds and streams where stock water, along nutrient-enriched seasonal watercourses and over wet ditch dredgings.

As far as moisture and disturbance requirements are concerned, this community is probably essentially the same as the Rorippa-Filaginella vegetation, being dependent on the exposure of moist soils and clays in the warmer weather of spring when ephemerals are best placed to capitalise on the congenial conditions. Hence, disturbance may often come, not from flooding, but from trampling by stock or by physical operations like the cleaning of silt from streams and ditches.

Synonymy

Suaedeto-Limonietum Chapman 1934 p.p.; Halimioneto-Limonietum Chapman 1934 p.p.;? Suaedetum fruticosae Tansley 1939 p.p.; Suaedeto-Limonietum binervosi Adam 1976; Halimiono-Frankenietum laevis Adam 1976 emend.; Norfolk Frankenia laevis stands Brightmore 1979.

Constant species

Armeria maritima, Halimione portulacoides, Limonium binervosum, Puccinellia maritima, Suaeda vera.

Rare species

Frankenia laevis, Limonium bellidifolium, L. binervosum, Suaeda vera.

Physiognomy

The rather open vegetation of this community is generally dominated by scattered bushes of Suaeda vera and Halimione portulacoides up to 40 cm high with a patchy cover of herbaceous halophytes between. Among the constants, Puccinellia maritima and Limonium binervosum are usually most abundant with smaller amounts of Armeria maritima. Suaeda maritima is fairly frequent throughout.

Sub-communities

Typical sub-community: Suaedeto-Limonietum binervosi Adam 1976. Festuca rubra, Plantago maritima and Artemisia maritima are frequent in this sub-community, the first sometimes in abundance. There are occasional records for a variety of species characteristic of disturbed places on the upper marsh and of strandlines.

Frankenia laevis sub-community: Halimiono-Frankenietum laevis Adam 1976 emend. Frankenia laevis and Limonium bellidifolium are constant in this sub-community which is more species-poor than the above.

Habitat

The community is characteristic of salt-marsh/dune interfaces, spit laterals, eroded dunes and some sanddune lows where there is a base of shingle covered with varying amounts of blown sand and inwashed silt (Chapman 1934, 1960b, Tansley 1939).

Synonymy

Rhodioletum roseae Nordhagen 1922 p.p.

Constant species

Festuca rubra, Armeria maritima, Rhodiola rosea, Rumex acetosa.

Physiognomy

The luxuriant herbaceous vegetation of this community has no single dominant. Usually, robust plants of Rhodiola rosea and Rumex acetosa and large cushions of Armeria maritima grow from a matrix of Festuca rubra in irregular and often fragmentary stands on cliff ledges. Plantago maritima, P. lanceolata and Holcus lanatus are frequent, the last sometimes occurring in abundance. Tall herbs such as Angelica sylvestris and Silene dioica may be prominent. No bryophytes were recorded.

Habitat

The Rhodiola-Armeria community occurs on ledges, mostly north-facing, above the most maritime zone on sea-cliffs. It is found on a variety of rock types where suitable ledges are developed: particularly fine stands may occur on prominently-bedded rocks such as the Old Red Sandstone of Caithness. The soils are irrigated rankers. Stands are quite inaccessible to grazing animals.

Zonation and succession

Stands of the community are generally discrete but may form part of a fragmented zonation up cliffs from the Armeria-Ligusticum maritime rock-crevice community to a more intact Festuca-Armeria maritime grassland or maritime heath above. On very tall cliffs, there may be a transition to less maritime ledge vegetation such as that described by Birks (1973) from Skye as the Luzula sylvatica-Silene dioica Association.

Synonymy

Includes Fumarietum officinalis R.Tx. 1950 and Fumarietum bastardii Br.-Bl. 1950.

Constant species

Capsella bursa-pastoris, Chenopodium album, Polygonum aviculare, Senecio vulgaris, Stellaria media.

Rare species

Fumaria bastardii.

Physiognomy

The Stellaria media-Capsella bursa-pastoris community is an annual vegetation type dominated by mixtures of Stellaria media, Capsella bursa-pastoris, Senecio vulgaris, Polygonum vulgare and Chenopodium album. Also more or less frequent overall but rather unevenly represented in the various sub-communities are Poa annua, Elymus repens, Chamomilla suaveolens and Urtica urens. More occasional are Sonchus asper, Cirsium arvense and Polygonum persicaria. Scarcer associates in the community include Rumex obtusifolius, Convolvulus arvensis, Solanum nigrum and Avena fatua.

Sub-communities

Typical sub-community. Apart from the species mentioned above, there is little that is distinctive about the vegetation here. Occasionally, Sinapis arvensis, Sisymbrium officinale and Lolium perenne are seen.

Matricaria perforata-Poa annua sub-community. Poa annua and, more particularly, Matricaria perforata are preferentially frequent in this sub-community along with common Agrostis stolonifera.

Fumaria officinalis-Euphorbia helioscopa sub-community. A number of quite common community associates, like Elymus repens, Veronica persica and Lamium purpureum are especially frequent here, but more striking is the preferential occurrence of Fumaria officinalis and Euphorbia helioscopa. More occasional are E. peplus, Sonchus oleraceus, Veronica agrestis, Mercurialis annua, Polygonum nodosum and Geranium dissectum. Around the coastal lowlands of western Britain, this vegetation provides a locus for the nationally rare Fumaria bastardii and, at scattered localities in England and Wales, for Chenopodium urbicum, probably an introduced plant.

Synonymy

Sperguletum marinae Tyler 1969.

Constant species

Spergularia marina, Puccinellia distans, P. maritima.

Physiognomy

The Puccinellietum distantis is a generally open association of scattered but often abundant individuals of Spergularia marina, Puccinellia distans and P. maritima with rather variable amounts of Agrostis stolonifera and sparse records for a variety of salt-marsh species (especially in coastal sites) and ruderal glycophytes. An algal mat is sometimes conspicuous in coastal stands but bryophytes are always rare.

Sub-communities

Sampling of coastal stands of the association has been insufficient to detect the existence of well-defined subcommunities but individual stands bear some resemblance to the Puccinellietum distantis polygonetosum R. Tx. 1956 emend. Beeftink 1962 (with Polygonum aviculare) and the Puccinellietum distantis pholiuretosum (with Parapholis strigosa) described from The Netherlands (Beeftink 1962, 1965, 1977a). Lee (1977) encountered inland stands similar to the ‘initial’ (with Atriplex hastata) and ‘degraded’ (without A. hastata and Spergularia marina) sub-associations recognised on Polish coastal marshes (Piotrowski 1974) and to the Puccinellietum distantis juncetosum Westhoff 1947 (with Juncus ambiguus Guss.) described from the Netherlands (Beeftink 1962). Lee's (1977) asteretosum is probably best considered in relation to the Aster tripolium communities of salt-marshes and brackish habitats. Further sampling is necessary to establish the validity of these sub-divisions in Britain.

Constant species

Bilderdykia convolvulus, Elymus repens, Matricaria perforata, Papaver rhoeas, Polygonum aviculare, Silene noctiflora, Stellaria media, Veronica persica.

Rare species

Silene noctiflora.

Physiognomy

The Papaveri-Sileneetum is an annual community in which Stellaria media, Matricaria perforata and Polygonum aviculare usually provide the bulk of the herbage, along with small ephemerals like Veronica persica, V. polita, Anagallis arvensis, twines of Bilderdykia convolvulus and young shoots of Elymus repens. The most striking feature, however, is the constancy of Papaver rhoeas and the nationally scarce Silene noctiflora, a plant whose peak of flowering is in mid-summer when the distinctive blooms, their yellow-backed petals inrolled until the cool of the evening, are seen most prolifically among cereal stubble or autumn-harvested crops.

Other frequent plants of this kind of vegetation are Chenopodium album, Agrostis stolonifera and Galium aparine with many occasionals including Fumaria officinalis ssp. wirtgenii, Viola arvensis, Aethusa cynapium and Linaria vulgaris.

Habitat

The Papaveri-Sileneetum is confined to light, well drained calcareous soils, mostly among cereals, across the warmer and drier south-east of England.

The most distinctive plant of this assemblage, S. noctiflora, has a more or less Continental distribution in Europe, rare in both the Mediterranean and Scandinavia, preferring better-drained soils and reproducing poorly in wet years (Stewart et al. 1994). With us, it has a marked south-easterly range, extending from Dorset to the Scottish border, where the climate is more congenial for its survival and where calcareous bedrocks are especially extensive.

Constant species

Chamomilla suaveolens, Plantago major, Poa annua.

Physiognomy

The Poa annua-Plantago major community comprises open swards in which rosettes of Plantago major and scattered plants of Poa annua and Chamomilla suaveolens are the only consistent feature. In contrast to the Polygonum-Chamomilla community, P. aviculare and Lolium perenne are of very variable frequency in the different sub-communities and Capsella bursa-pastoris is never more than occasional. The scarcity of Matricaria perforata and Elymus repens provide a distinction from the Poa-Matricaria community. Agrostis stolonifera and Taraxacum officinale agg. are occasional through the community and there are scarce records for Rumex crispus, R. obtusifolius, Bellis perennis, Filaginella uliginosa, Medicago lupulina, Alopecurus geniculatus, Anagalllis arvensis and Senecio vulgaris.

Sub-communities

Typical sub-community. Few species other than the three community constants occur with any frequency here but occasionally there is some Lolium perenne, Polygonum aviculare, Agrostis stolonifera and Taraxacum officinale. More distinctive is the presence in some samples of Sagina procumbens and Bryum argenteum.

Lolium perenne sub-community. L. perenne is a constant associate here with occasional Capsella bursa-pastoris, Polygonum arenastrum, Trifolium repens, Ranunculus repens, Agrostis stolonifera and Taraxacum officinale agg.

Polygonum aviculare-Ranunculus repens sub-community. L. perenne remains quite frequent here, along with Trifolium repens but more distinctive is the common occurrence of P. aviculare, R. repens, A. stolonifera and T officinale agg. with occasional Potentilla anserina, Matricaria maritima, Cerastium fontanum, Stellaria media, Polygonum persicaria, P. lapathifolium, P. hydropiper, Holcus lanatus and Dactylis glomerata.

With something as complex and variable as vegetation, no key can pretend to offer an infallible short cut to diagnosis. The following should thus be seen as simply a crude guide to identifying the types of vegetation found on maritime cliffs and must always be used in conjunction with the data tables and community descriptions. It relies on floristic (and, to a lesser extent, physiognomic) features of the vegetation and demands a knowledge of the British vascular flora and, in only a few cases here, of bryophytes and lichens. It does not make primary use of any habitat features, though these may provide a valuable confirmation of a diagnosis.

Because the major distinctions between the vegetation types in the classification are based on inter-stand frequency, the key works best when sufficient samples of similar composition are available to construct a constancy table. It is the frequency values in this (and, in some cases, the ranges of abundance) which are then subject to interrogation with the key.

Samples should always be taken from homogeneous stands and be 2 × 2 mor 4 × 4 m according to the scale of the vegetation or, where stands are irregular, of identical size but different shape.

Constant species

Agrostis capillaris, Campanula rotundifolia, Festuca ovina, Minuartia verna, Thymus praecox.

Physiognomy

The Minuartio-Thlaspietum alpestris characteristically comprises an open turf in which tussocks of Festuca ovina, patches of Agrostis capillaris and scattered individuals or populations of Minuartia verna are the most prominent feature. Thymus praecox is also constant and its mats can be locally quite extensive and there is very often a little Campanula rotundifolia and Rumex acetosella. Among the more frequent associates of the community, Thlaspi alpestre is the most distinctive, though it is typically not abundant.

Other species recorded commonly throughout, though not usually in any abundance, are Rumex acetosa, Senecio jacobaea, Linum catharticum and, particularly in transitions to more continuous calcicolous and mesotrophic swards, Lotus corniculatus and Trifolium repens. Occasionals of the community include Geranium robertianum, Cerastium fontanum, Hieracium pilosella, Cirsium vulgare, Agrostis stolonifera and Viola lutea.

Through the community as a whole, bryophytes are neither numerous nor extensive, though small patches of Pohlia nutans, Weissia controversa and Dicranum scoparium can sometimes be seen. Lichens, too, are absent from many stands but strikingly varied and abundant in one sub-community.

Sub-communities

Typical sub-community:Minuartio-Thlaspietum typicum Shimwell 1968a. In this vegetation, Minuartia verna, Festuca ovina (here occasionally joined by F. rubrd) and Agrostis capillaris dominate the sward with a typical range of community associates. In stands from the Yorkshire Dales, Galium sterneri is a distinctive associate.

Synonymy

Shingle beach community Oliver 1911, Oliver & Salisbury 1913, Tansley 1939, all p.p; Glaucium flavum sites Scott 1963 p.p.; Crithmo-Crambetum maritimae (Géhu 1960) Géhu & Géhu 1969 p.p.; Lathryo-Crambetum maritimae Géhu & Géhu 1969; Crambe maritima sites Scott & Randall 1976 p.p.; Rumici-Lathyretum maritimi Géhu & Géhu-Franck 1979.

Constant species

Glaucium flavum, Rumex crispus.

Rare species

Crambe maritima.

Physiognomy

The Rumex crispus-Glaucium flavum community comprises more or less open assemblages of rather coarse hemicryptophytes, usually few in number and with none consistently dominant, but together giving a highly distinctive character to the stretches of bare shingle or gravel that form the typical habitat, especially when the plants are fully grown in flower or fruit. The commonest species overall is Rumex crispus, generally with the obviously tri-tubercular perianths and dense panicles of var. littoreus Hardy (which now includes var. trigranulatus Syme: Lousley & Kent 1981, Rich & Rich 1988), the tall inflorescences remaining upstanding, brown and brittle, at the close of the season. Glaucium flavum is also constant and sometimes very abundant. It behaves as a short-lived perennial, each plant having one to many biennial leaf-rosettes, these persisting through their first winter, with the tall, branched flowering stems growing up in spring. Both these inflorescences and the foliage die after fruiting, but several new rosettes replace each old one before winter, such that colonies expand progressively from one season to the next (Scott 1963b).

Constant species

Chrysanthemum segetum, Poa annua, Polygonum aviculare, Spergula arvensis.

Physiognomy

The distinctive feature of the annual vegetation of the Spergulo-Chrysanthemetum is the constancy of Spergula arvensis and Chrysanthemum segetum, the latter often abundant and especially striking by summer with its big, bright yellow flower heads. Poa annua and Polygonum aviculare are also constant in the community, Elymus repens, Capsella bursa-pastoris and Stellaria media frequent. Occasional occurring throughout are Bilderdykia convolvulus, Misopates orontium, Euphorbia helioscopa and Chamomilla suaveolens. The perennial grasses Elymus repens and, somewhat less commonly Lolium perenne and Agrostis stolonifera can get a hold each year, though renewed disturbance curtails their continuing growth.

Sub-communities

Typical sub-community. In this sub-community, the only additional distinguishing features are frequent records for Matricaria perforata and occasional Poa trivialis, Polygonum lapathifolium, Fumaria muralis ssp. boraei and Lamium purpureum.

Ranunculus repens-Sonchus asper sub-community. Here, Ranunculus repens and Sonchus asper are strongly preferential with Polygonum persicaria and Potentilia anserina also frequent and occasional records for Anagallis arvensis, Viola arvensis, Myosotis arvensis, Crepis capillaris, Vicia sativa ssp. nigra and the perennials Bellis perennis, Trifolium repens, Holcus lanatus, Cerastium fontanum and Plantago major.

Habitat

The Spergulo-Chrysanthemetum is a widespread community of disturbed, light, fertile acidic soils throughout the British lowlands, and a common feature of both cereal and root crops.

Synonymy

Holcetum lanati Gillham 1953 p.p., Goodman & Gillham 1954 p.p.; Sileno maritimae-Festucetum pruinosae R. Tx. 1963 p.p., Armerieto maritimae-Daucetum gummiferi Géhu 1964 p.p., includes Festuco-Dactyletum maritimae Malloch 1971.

Constant species

Festuca rubra, Holcus lanatus, Plantago lanceolata, Armeria maritima.

Rare species

Allium schoenoprasum, Astragalus danicus, Oxytropis halleri, Primula scotica, Scilla verna, Senecio integrifolius ssp. maritimus, Trifolium occidentale.

Physiognomy

The Festuca-Holcus maritime grassland generally has a closed fairly low-growing but rather rank and often tussocky sward. It is almost always dominated by grasses of which F. rubra is usually the most prominent, though H. lanatus and, to a lesser extent, Dactylis glomerata, are often abundant. Herbaceous dicotyledons are generally an important component of the vegetation and many of these are non-maritime species. Armeria maritima and Plantago lanceolata are both constant and Plantago maritima, Rumex acetosa and Trifolium repens are frequent throughout. Bryophytes and lichens are rare.

Sub-communities

Plantago maritima sub-community. F. rubra is the usual dominant in the thick sward of this sub-community, though H. lanatus and, less frequently, Agrostis stolonifera and, in the north, Poa subcaerulea, may be abundant in particular stands. Plantago maritima, Trifolium repens and Lotus corniculatus are additional constants here and P. maritima is sometimes so abundant as to be a co-dominant, especially where there is a shorter grazed turf. Scilla verna is frequent, though never abundant, and Astragalus danicus, Primula scotica and Senecio integrifolius ssp. maritimus occur occasionally within their ranges of distribution.

Synonymy

Allium schoenoprasum-Plantago maritima community Hopkins 1983

Constant species

Allium schoenoprasum, Festuca ovina, Plantago maritima, Scilla verna.

Rare species

Allium schoenoprasum, Isoetes hystrix, Juncus capitatus, Scilla autumnalis, S. verna.

Physiognomy

The Allium schoenoprasum-Plantago maritima community comprises usually sparsely scattered individuals of perennial and ephemeral plants occuring as diverse mixtures in very small stands, often less than 1 m2 in extent, and with a marked annual pattern of growth. Most of the species are perennial, though few of these are constant or of consistently high cover. However, after the damper weather of winter and with the flushing that is a characteristic feature of the habitat of this vegetation, the scattered usually dimutive tussocks of Festuca ovina and Armeria maritima and the rosettes of Plantago maritima show a flush of green growth in spring and are joined by the emerging shoots of Scilla verna and Allium schoenoprasum. Twisting leaves of the latter are especially distinctive in the sward and the species is often the most abundant plant with cover values exceeding 25%. It also flowers prolifically here, with a profusion of pretty pink dwarf inflorescences, unlike many of the other species which remain vegetative.

Among the associates, dwarfed plants of Calluna vuhgaris are frequent and occasionally there can be some Scilla autumnalis, Thymus praecox, Galium verum, Centaurium erythraea, Polygala vulgaris, Carex flacca, Minuartia verna, Agrostis stolonifera, A. canina ssp. montana and Koeleria macrantha.