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Veronica spicata L. ssp. spicata and ssp. hybrida (L.) Gaudin ( Pseudolysimachium spicatum (L.) Opiz)

2000; Wiley; Volume: 88; Issue: 5 Linguagem: Inglês

10.1046/j.1365-2745.2000.00501.x

1365-2745

G. B. Wilson, L. Houston, W. J. Whittington, R. N. Humphries,

Plant-derived Lignans Synthesis and Bioactivity

Subgenus Pseudolysimachium. Pubescent perennial herb. Shallow roots, white, fine and fibrous. Tap-roots 1.5 mm diameter, light brown, sparsely branched, but roots mostly adventitious, often into cracks and crevices of fragmented rocks. Rhizomes/stolons somewhat woody, shortly creeping and rooted or long and thick, less than 10 cm deep, arising above or below ground level. Stock shortly creeping, hard, almost woody. Stems erect, woody near base, ascending or spreading, e.g. near scrub edge or at cliff edges hanging down before ascending at or in the spike. Stems to 30 cm in ssp. spicata[in ssp. hybrida 60–85(−100) cm], stout, more or less densely hairy and glandular, rarely glabrous. Leaves decussate, 15–80 × 2–30 mm, lower ovate or oval crenate, sometimes doubly crenate, becoming linear-lanceolate, crenate-serrate or upper leaves sometimes entire or sessile. Petioles 0–30 mm. Lowest leaves of ssp. spicata 15–30 × 8–12 mm, crenate-serrate only at widest part (nearly middle), gradually narrowed into petiole; in ssp. hybrida lowest leaves 20–40 × 10–20 mm, usually crenate-serrate along most of the margin, widest below the middle and abruptly narrowed into the petiole. Inflorescence a many-flowered terminal spike-like raceme. Mostly single, occasionally with up to 10 or more lateral inflorescences in ssp. hybrida, usually smaller than main inflorescence, arising from axils of stem leaves; rarely the spike itself splits. Pedicels very short, 0.5 mm. Bracts 1–3 × 1–1.5 mm, broadly lanceolate, one per flower. Sepals 4, occasionally 5, 1–2.5 × 2–6 mm, lanceolate to triangular acute, glandular hairy, plus long glandless cilia (Fischer 1974); lower third of sepals joined. Corolla violet-blue, occasionally deep blue-purple, rarely white, pink or lilac, tube joined at lower third, 3 mm. Petals 4, 4–6 × 1.5–3 mm, ovate-lanceolate; flat lower lobes of upper petal tend to be wider than the other three. Stamens 2; pollen 12 × 29 µm, yellow. Carpels two, stigma discoid. Capsule 2–4 × 2–4 mm, heart-shaped, retuse, emarginate, about as long as the calyx lobes, 2-chambered, style 4–10 mm. Seed 0.8 × 0.5 mm, ovoid, air-dry mass 0.082 ± 0.0001 mg, dark brown, with narrow deep vertical groove; radicle prominent. Stace (1997) maintains the division of British populations of V. spicata into two subspecies, ssp. spicata and ssp. hybrida, whereas the species in continental Europe is not divided. Stace (1997) distinguishes ssp. hybrida as 'usually…taller and having larger, more extensively crenate-serrate leaves that are widest below (not at) the middle and are more abruptly narrowed into the petiole, but the differences are not constant and these races are only two of a large number in Europe'. Veronica spicata is a plant of limestone rocks and of dry grassland on basic soils. It is of particular interest because of its wide distribution in Europe, its disjunct distribution in Britain where it is listed on Schedule 8 of the Wildlife & Countryside Act 1981 and the potential threat to ssp. spicata in eastern Britain. The latter was recorded in four 10-km squares of the National Grid in the period 1987–97 and is classified as vulnerable (VU) in the Red Data Book (Wigginton 1999). Veronica spicata is largely limited to the southern half of the British Isles (1, 2). Subspecies spicata is found only in the east of Britain, in the Watsonian Vice-counties of Cambridgeshire, W. Norfolk and W. Suffolk. Subspecies hybrida is classified as nationally scarce (Kay 1994) with some 20 known locations to the west of Britain. In Wales, these are in Vice-counties Caernarvonshire, Carmarthenshire, Denbighshire, Flintshire, Glamorganshire, Merionethshire, Montgomeryshire, Pembrokeshire and Radnorshire; in England in W. Yorkshire, Westmorland, W. Gloucestershire and N. Somerset. Populations vary between sites from a few clumps to several thousand. Those of Breidden Hill (Montgomeryshire) and the Avon Gorge (W. Gloucestershire/N. Somerset) have been particularly studied. Townsend (1883) reported two locations in Hampshire for V. spicata and one in the Isle of Wight. All three records appear to have been errors (L. C. Frost, pers. comm.). The distribution of Veronica spicata ssp. spicata in the British Isles. Each dot represents at least one record in a 10-km square of the National Grid. (○), pre-1950; (●), 1950 onwards. Mapped by Mrs J.M. Croft, Biological Records Centre, Institute of Terrestrial Ecology, Monks Wood. The distribution of Veronica spicata ssp. hybrida in the British Isles. Each dot represents at least one record in a 10-km square of the National Grid. Native: (○), pre-1950; (●), 1950 onwards; introduced: (+), pre-1950; (×), 1950 onwards. Mapped by Mrs J.M. Croft, Biological Records Centre, Institute of Terrestrial Ecology, Monks Wood. Pigott & Walters (1954) stated that the differences between the two subspecies were largely ecotypic and that European systematists regarded them both as falling within V. spicata. Citing Härle (1932), they referred to its variability over its wide Eurasiatic range. In Fl. Eur. 3, p. 251, ssp. hybrida is not separated. Matthews (Dist. Brit. Fl.) described Veronica spicata L. as a true Continental species with a European distribution from Scandinavia to central Spain, through Italy, Greece and west and central to north Asia. It is absent from the Arctic and more Mediterranean regions. Preston & Hill (1997) list V. spicata as Eurosiberian Temperate and Continental in Europe. In western Europe it is generally rare. Bonnier (1911–35) referred to its very unequal distribution in France, noting it as common in the Pyrénées and the Rhône basin but rare in the Auvergne, Burgundy and Normandy and absent from Limousin and the Corbières. It was quite common around Paris. In the former West Germany V. spicata occurred in just over one hundred 10-km squares, i.e. about 6% of the whole, mostly in the southern half of the country, in four main concentrations centred on the Hunsrück Mountains and near Schweinfurt, Donaueschingen and Ingolstadt (Haeupler & Schönfelder 1988). It becomes more common in eastern Europe and is an important component of the Russian steppes (Fig. 3). The distribution of Veronica spicata in Europe (Vergl. Chor.). In Britain, V. spicata usually grows on low ground at an altitudinal range of up to about 400 m (Alt. range Brit. Pl.), but on the Alps it is found up to 1850 m (Bonnier 1911–35). Ellenberg (1988) gives the altitudinal range as 77–525 m. Pigott & Walters (1954) were concerned with those species which occur in isolated habitats within the British Isles but more commonly and continuously over a part, often a large part, of the European continent. They identified seven different habitats where communities with such species occur, among which were inland cliffs and screes, sea cliffs, river gorges, sand dunes and dune slacks, and shallow soils over chalk and limestone, especially on steep slopes. These very much reflect the range of habitats of V. spicata in Britain and northern and western Europe as a whole, from inland and sea-cliff ledges, bare rocky slopes, screes and limestone pavement to dry grassland. Pigott & Walters (1954) noted that the factors common to those habitats were the presence of basic rock or base-rich drainage water and the absence of natural dominant woodland. More crucially such habitats could never have supported closed woodland, even at the time of maximum post-glacial forest development, for reasons such as steepness or shallowness or instability of soil. They concluded that V. spicata with many of its associates in their scattered sites represented relict communities of a once widespread late-glacial 'steppe-tundra' vegetation, most of which in north-west Europe had been lost under closed forest. They also suggested that some species now characteristic of the East Anglian heaths may have survived the period of dominant woodland in small numbers in open vegetation of the 'steppe' grassland type, maintained by river erosion, with subsequent expansion following the clearance of woodland by Neolithic man. Pigott & Walters (1954) described V. spicata as highly intolerant of shade and competition, persisting only where potentially tall competitors remained restricted by relative harshness of environment, by soil instability, or by rabbit-grazing or mowing. However, they indicated that the rare species of Breckland could survive in sparse woodland and noted that Schmid (1936) referred to V. spicata occurring under these conditions in the Alps and Carpathians. On Breidden Hill, the main population of ssp. hybrida occurs on dry, open, sun-baked south-facing shelves with a few plants on rock ledges on the South and West Crags. Jones (1993) found 'probably the largest population…in Wales' at Cefn Rocks and Bryn Cefn Woods in Denbighshire, the main site a west-facing inland cliff. In the Avon Gorge the subspecies grows throughout the cliffs of St Vincent's Rocks and (the lesser) Burwalls Rocks, at its southern end (Lovatt et al. 1993). Wade et al. (1994) described ssp. hybrida in Glamorgan at three sites, growing on shallow soils near outcrops and in rock crevices on Carboniferous limestone sea-cliffs; similar locations with larger populations are found on the Great Orme, Caernarvonshire and Humphrey Head, Westmorland. Subspecies hybrida also occurs in grazed pastures, e.g. at Far Arnside, Westmorland. In East Anglia, Veronica spicata ssp. spicata is limited to a flatter habitat of dry grasslands and sandy heaths. In the west of Britain ssp. hybrida experiences an oceanic climate with a relatively high annual rainfall (1000 mm) and mean January and July temperatures of 6–17 °C. The Breckland sites of ssp. spicata have a more continental climate with a relatively low annual rainfall (625 mm) and mean January and July temperatures of 3–16 °C. Aspect appears to be an important factor in the slightly milder western climate: the cliff sites of ssp. hybrida are predominantly south-to-west facing, receiving high insolation in the afternoons when the sun is most effective. While ssp. spicata is subjected to a lower winter temperature, both subspecies can survive drought in summer when temperatures on exposed rock faces such as the Avon Gorge cliff habitat of ssp. hybrida may exceed 50 °C. In western France, where Carboniferous cliff and gorge habitats are absent, V. spicata is found on chalk grassland, clearings in woods on calcareous soils and on sand dunes in scattered localities (Pigott & Walters 1954). In Finland, at the northern limits of its distribution (about 60°N), V. spicata occurs only in the south of the country (Kukkonen 1986). The sites are very dry, again facing south or south-west, on rocky outcrops and the surrounding shallow soils from < 10–120 m a.s.l. On the Swedish island of Öland the species occurs on short, grazed grassland on 'alvar', a horizontal pavement with little loose material and vegetation mostly in the cracks (Rosén 1982; van der Maarel & Sykes 1993). Oberdorfer (Pfl. Exk.) and Hegi Fl. ed. 1, 6.1 in Germany, and Hess et al. (1967) in Switzerland, described V. spicata as associated with dry conditions. Oberdorfer (1978) refers to its occurrence on the hilly–mountainous regions of Bavaria, Hessen and the Rhineland Palatinate such as the Black Forest, the Erzgebirge, the Kaiserstuhl and Harz and Jura mountains. Keller (1927) suggested that the most important factors in determining the characteristic Russian vegetation were the great glaciers which formerly covered the plains, and the waters of the Caspian basin which at one time spread over much of the south-east. Veronica spicata was associated with dry sands and steppe. Soils in the UK supporting V. spicata ssp. hybrida are usually shallow, stony loams, or sandy or humic overlying limestone, shale or base-rich rocks such as dolerite on Breidden Hill and Stanner Rocks (Radnorshire). In the Avon Gorge sites of ssp. hybrida, Lovatt (1982) reported that the soils are 'commonly rendzinas, shallow and dark highly humic soils directly overlying the limestone', with a pH of 7.3–8.2. A reddish-brown silty clay loam (Lulsgate series) is also present. Lovatt (1982) suggested soil type as a determinant of the plant's localization at the south end of the Gorge. Houston (1986), however, believed that the irregular, fault-shattered nature of the rock in this area, with its many seepage cracks, was the more significant factor. On Breidden Hill the soil in the areas colonized by ssp. hybrida is podsolic, moderately acid but fairly base-rich (Jarvis 1971). A similar range of soils is described for V. spicata localities in Europe (Oberdorfer 1978). It has also been found on deep, black earth soils and sodium carbonate rich solonets soils in Russia (Keller 1927). Jarvis (1971) analysed soils from three British sites (Breckland, Breidden Hill and Stanner Rocks). The base status of the Breckland soil was considerably higher than that of the others. It was argued that soil conditions at Breidden Hill are not ideal for the species since the addition of carbonate and an increase in pH, or transplantation to a limestone soil, resulted in increased growth. Breckland soils bearing ssp. spicata are derived from chalky glacial drift and interglacial sands. These are moderately acid to basic, alkaline and base-rich, but with low to medium nutrient content. On Newmarket Heath, Cambridgeshire, Coombe (1987) described the occurrence of distinct patterning from periglacial freezing and thawing, with alternating patches of shallower calcareous soil and deeper non-calcareous sand, described as 'stripes' on slopes and 'polygons' (reticulations) on level ground. He stated that the sites 'are usually on the Middle Chalk, but always where the solid chalk is covered first with a mantle of "head"or soliflucted sludge, over which are very varying depths of red sandy and often non-calcareous loams'. On Burwell Heath, Cambridgeshire, Coombe (1988) noted a large colony of ssp. spicata on the 'stripes' of deep sandy soil. Veronica spicata ssp. spicata is virtually confined to this soil (pH 5.5) rather than the chalky soil associated with the reticulations. Watt (1971) reported mean values and ranges for calcium, magnesium, potassium and phosphate contents of Breckland soils with a pH value of 6.7 (5.6–8.0). Birkinshaw (1990) noted pH values ranging from 4.4 to 6.75 for seven populations of ssp. spicata on Weeting Heath (W. Norfolk). D. E. Coombe (pers. comm.) has observed that pH can vary sharply over short distances on Breckland soils. This was also found in analyses of soil from the Great Orme (pH 5.2–7.2), but soils from the Avon Gorge (pH 7.3–7.6), Gower (pH 7.2–7.4) and Humphrey Head (pH 6.8–7.5) were more consistent (G. B. Wilson, unpublished). Watt (1971) suggested that Breckland soils remained immature because the products of weathering were removed by soil fluction, leaving them shallow and dry and therefore unable to sustain trees capable of forming a closed canopy. In Sweden, on Öland, the species is found in grassland on 10–50 cm deep, slightly acid to neutral, brown soils developed on re-worked glacio-fluvial deposits on Ordovician limestone (Rosén 1982; Krahulec et al. 1986). In Germany Ellenberg (1988) described the species as indicative of fairly acid soils, occasionally growing in more acid, or in neutral to slightly alkaline, situations and tending to occur in soils deficient in nitrogen. Ellenberg (1988) noted that grazing and cutting the vegetation for animal consumption removed nutrients and contributed still further to the low inherent fertility of the natural grasslands in which V. spicata is commonly found. Matthews (Dist. Br. Fl.) regarded the species as semi-xerophytic, a member of the Trockenrasen community. Rodwell (1992) lists V. spicata as a rare species in five communities of the National Vegetation Classification: Festuca ovina–Carlina vulgaris grassland (CG1), Festuca ovina–Avenula (Helictotrichon) pratensis grassland (CG2), Festuca ovina–Hieracium pilosella (Pilosella officinarum)–Thymus praecox (polytrichus)/pulegioides grassland (CG7), Sesleria albicans (caerulea)–Galium sterneri grassland (CG9) and Festuca ovina–Agrostis capillaris–Rumex acetosella grassland (U1). Veronica spicata is further classified as belonging to the Filipendula vulgaris–Helianthemum chamaecistus (nummularium) variant of the Cirsium acaule–Asperula cynanchica subcommunity of CG2; to the Cladonia spp. subcommunity of CG7; to the Helianthemum (oelandicum) canum–Asperula cynanchica subcommunity of CG9; and to the Hypochaeris radicata subcommunity of U1. Festuca ovina is a constant member of all five communities. The few other species common to the lists include Anthyllis vulneraria, Lotus corniculatus and Plantago lanceolata. Pilosella officinarum occurs in CG1, CG2, CG7 and CG9, but P. peleteriana in the U1 (Breidden) subcommunity. Otherwise, Thymus polytrichus ssp. britannicus is constant in the four CG communities. R. A. Jones (pers. comm.) has reported V. spicata in a sixth community, CG6 (Avenula (Helictotrichon) pubescens grassland). Birkinshaw (1990) noted that 'In Cambridgeshire, V. spicata occurs in a mown "Bromus erectus (Bromopsis erecta)" community (as defined by the NVC) on a well-drained, drought susceptible, oligotrophic, more or less calcareous brown earth/rendzina', i.e. CG3. On Breidden Hill, S. M. Walters (pers. comm. 1955) found V. spicata ssp. hybrida abundant on a small ridge running south from the West Crags where Aira praecox and Teucrium scorodonia were also abundant, Erica cinerea and Veronica officinalis frequent, and Cerastium fontanum and Senecio jacobaea occasional. Seventeen other flowering species were recorded. On the South Crags, Wilson et al. (1987) found the plant in two distinct situations and associate groups. Where it occurred on open south-facing cliff ledges, the number of occasions when other species were found within 0.3 m was as follows: Festuca ovina 5; Pilosella peleteriana 3; Helianthemum nummularium 2; Thymus polytrichus ssp. britannicus 2; Teucrium scorodonia 1; Ulex europaeus 1; (no other species 9). Jarvis (1971) had classified V. spicata ssp. hybrida in a phytosociological grouping with Lychnis viscaria and Umbilicus rupestris on the cliff faces, but neither species was scored in direct association with it by Wilson et al. (1987). The greater part of the population was recorded on dry grassy shelves above the crags, in areas of bare soil but also in dense swards of Festuca ovina, often adjacent to or even under the mixed calcicole/calcifuge scrub or woodland edge vegetation, with Calluna vulgaris, Erica cinerea and Helianthemum nummularium. Sinker et al. (1986) described this as 'a distinct rock heath community' similar to the grass heath community recorded by Tansley (Tansley, Br. Isl.). Wilson et al. (1987) found Pilosella peleteriana strongly associated with V. spicata ssp. hybrida in two surveyed areas, occurring in 50% and 75% of 30 × 30 cm thrown quadrats which also contained abundant winter annuals such as Aira praecox, Myosotis ramosissima, Ornithopus perpusillus and Teesdalia nudicaulis. Overall, the association with F. ovina, H. nummularium and P. peleteriana was most evident. In the Avon Gorge Lovatt (1982) described four distinct vegetation units in which V. spicata ssp. hybrida occurred in a continuous range of vegetation on St Vincent's and Burwalls Rocks (Table 1). The most typical (Group 1) had a high constancy of Mesobromion species. Group 2, on less steep slopes (5–30°, mean 16°), consisted mainly of ruderal and alien species typical of nutrient-rich soils, while Group 3, on deeper soils, had a low constancy of calcicoles with an increase in scrub shade and hedgerow grassland plants. Group 4, on the shallowest soils and occupying a zone on the edges of ledges or rock pockets, had a higher proportion of therophytes. Lovatt (1982) also gave results from 49 (1-m2) quadrats from throughout the Avon Gorge sites (Table 2a), while G. B. Wilson (unpublished) recorded species associated with V. spicata ssp. hybrida at eight western sites (Table 2b). Overall Festuca ovina was the most frequent associate, followed by Sanguisorba minor, Dactylis glomerata, Scabiosa columbaria and Helianthemum nummularium. Species associated with ssp. spicata were recorded by Crompton (1974–86) at two sites on the Beacon Course at Newmarket, Cambridge (Table 3). The fine-leaved fescues (Festuca ovina with F. rubra) and Bromopsis erecta were most frequent, together with Filipendula vulgaris, Galium verum and Koeleria macrantha. Birkinshaw (1990), citing G. Crompton (unpublished), reported that the grass where the population on the racecourse grew, which was formerly grazed, was now mown. This had encouraged growth of Bromopsis erecta at the expense of fine-leaved fescues and the chamaephytes, hemicryptophytes and therophytes also found on dry calcareous brown earth rendzina soils. Records from five sites collected by G. Crompton, L. Farrell, F. Rose, M. Southwell and A. S. Watt were also included by Birkinshaw (1990) and the most frequently occurring species in three of these, together with a list prepared by Trist (1979), are given in Table 4. Tables 1–4 show that the following species in particular are associated with both V. spicata subspecies in Britain: Arenaria serpyllifolia, Bromopsis erecta, Dactylis glomerata, Festuca ovina, Helianthemum nummularium, Sanguisorba minor, Plantago lanceolata and Thymus polytrichus ssp. britannicus. Lovatt (1982) reported that in 1951 D. E. Coombe had recorded V. spicata in a 'pure steppe slope' on the Rotenfels in Austria. In a south-east facing association between woodland and the cliff edge Bromopsis erecta was dominant, Carex humilis abundant, Helianthemum nummularium and Clinopodium acinos occasional and V. spicata rare. Aster linosyris was the only other British species present. Pigott & Walters (1954) referred to the fact that species of Meusel's (1940) grass heath groups (the continental and the Atlantic–sub-Atlantic) could be found interspersed in Breckland, rather than in proximity but separated. They believed that such species, differing in their ecological and edaphic preferences, were survivors of post-glacial climatic fluctuations which favoured different species at different times and thus encouraged diversity. In Europe, Ellenberg (1988) considered that the arid and semi-arid grasslands in which V. spicata is found owed their existence to events over the last two thousand years of climatic change and the influence of man in removing the natural woodland. This was replaced by grassland on the less fertile soils, which was either grazed by farm stock or cut for animal feed. This type of habitat is now becoming less frequent as agricultural practices change, so that the number of locations suitable for V. spicata and similar species may become fewer and more isolated. Oberdorfer (1978) refers to V. spicata within two classes: the Sedo–Scleranthetalia and the Festuco–Brometea with its orders Festucetalia valesiacae (alliances Festucion valesiacae and Cirsio–Brachypodion) and Brometalia (alliances Xerobromion, Mesobromion, Koelerio–Phleion phleoidis and Mesobromion erecti). Ellenberg (1988) commented that because of their lime and clay content the calcareous grasslands (Festuco–Brometea) are particularly rich in species and easily separated from the siliceous and sand grasses (Sedo–Scleranthetalia) which are usually absent from average or fertile soils. The Festuco–Brometea also occupy a far larger area of central Europe than the Sedo–Scleranthetalia. He further commented that the Festucetalia valesiacae lead on 'to the continental steppes' while the Brometalia recall 'the grass heaths of west and southern Europe'. Keller (1927) has described V. spicata within a number of plant communities of the Russian plains. Herbaceous and dwarf shrub species, e.g. Antennaria dioica, Artemisia campestris, Campanula rotundifolia, Filipendula vulgaris, Genista tinctoria, Jasione montana, Pilosella officinarum and Silene otites, were recorded with Koeleria macrantha on sandy and rocky soil of pine forests (Pinetum cladinosum). Veronica spicata was also found in grass steppe, on deep black earth soils, chernozem, dominated by turf grasses and rosette-forming herbs such as Achillea nobilis, Bromopsis erecta, Festuca rupicola ssp. rupicola, Filipendula vulgaris, Koeleria macrantha and Trifolium repens, and in a second type of this community dominated by Helictotrichon desertorum. On drier soils with decreased leaching and accumulated salts, particularly sodium carbonate, solonets soils develop, with herbaceous species such as Bassia prostrata, Limonium gmelinii, Serephidium maritimum and Silaum silaus amongst the turf grasses. Keller (1927) also reported that V. spicata occurred in the Alpine region of the Altai in association with species of Achillea, Campanula, Galium, Myosotis and Senecio. He believed that 'these probably lived at one time close to the limits of the glaciers on the East European plains'. In Sweden V. spicata occurs in the short grassland assigned to the Veronica spicata–Avenula (Helictotrichon) pratensis association (Krahulec et al. 1986). Andersson (1950) described V. spicata as growing in dry, sandy calcareous grassland with Briza media, Festuca ovina, Helictotrichon pratense, Medicago sativa ssp. falcata and Thymus serpyllum. Van der Maarel & Sykes (1993) in a six-year study in the southern part of Öland noted 39 species in the quadrats studied, of which 20 also occur within one or more of Tables 1–4. On the Stora Alvaret in Öland, Rosén (1982) did not find V. spicata in either grazed or ungrazed Festucetum vegetation, but it occurred consistently in the Avenetum vegetation, particularly with Arrhenatherum pratense, Festuca ovina, Filipendula vulgaris, Galium verum, Lotus corniculatus, Potentilla spp. and Sedum acre. Kukkonen (1986) mentions 33 species of flowering plant found variously in association with V. spicata at 17 sites in Finland. These are listed in Table 5. On the summits of kame hills in Poland, Falinski (1972) reported V. spicata in the association Phleo–Veronicetum, a poorer form of the order Festucetalia valesiacae in the class Festuco–Brometea. These are xerothermal grasslands, mostly closed with few bare soil patches, with Artemisia campestris, Filipendula vulgaris, Galium mollugo, Medicago sativa ssp. falcata, Plantago media and Pimpinella saxifraga. Oberdorfer (1978) gives composite tables from survey data provided by various authors from different sites which show species composition within the Festuco–Brometea in Germany. Taken together they show that Veronica spicata is a common, but not constant, component of the surveys. It occurs in 20 out of the 48 contributing groups and, within these, has a mean frequency of occurrence of 16.7%. In comparison with the other species mentioned with those for Britain and Finland (Tables 1–5), Achillea millefolium, Dactylis glomerata, Festuca ovina, Filipendula vulgaris, Galium verum, Helianthemum nummularium and Sanguisorba minor are common associates of V. spicata, and all except the second and last of these were mentioned by van der Maarel & Sykes (1993) in their work on Öland. In Hungary, V. spicata was noted occurring commonly on the limestone hills of the south-west outskirts of Budapest, associated with species including Aster linosyris (f), Carex humilis (a), a fine-leaved Festuca sp., Helianthemum oelandicum (a), Melica ciliata, Teucrium chamaedrys and T. montanum; the topography and physiognomy recalled the dry open grasslands of the limestone hills and headlands of the North Wales coast. Just east of the Turda Gorge in Romania, c. 30 km SSE of Cluj-Napoca, V. spicata was frequent on a rocky limestone slope with scattered bushes, reminiscent of the Cheddar area of Mendip. Species present in addition to those given above included Allium flavum, Asperula cynanchica, Helianthemum nummularium, Iris sp., Medicago sativa, Phleum phleoides, Stipa lessingiana and the shrub species Cornus sanguinea, Cotoneaster integerrimus and Euonymus europaeus (M.C.F. Proctor, pers. comm.). The species in common between various of the studies indicate similarities in overall environmental conditions at those sites across Europe where V. spicata is found. They may be seen as part of a broad European pattern of which we have in Britain the frayed western edges on the East Anglian chalk and on our west-coast limestones (M.C.F. Proctor, pers. comm.). Grazing undoubtedly plays an important role in the structure and survival of V. spicata populations. Pigott & Walters (1954) refer to rabbit-grazing as a key factor in suppressing competitors and maintaining an open habitat. Twelve of the 15 extant Welsh sites of ssp. hybrida are wholly or partially grazed, by rabbits (10 sites) and/or sheep (6 sites), with evidence of deer also at 3 unstocked sites; the remaining sites or part-sites are precipitous and inaccessible to grazers (D. Guest, pers. comm.). Stems and inflorescences, however, are vulnerable to grazing damage and appear particularly attractive to rabbits (Rich 1997). Where the plant is subject to hard and continuous sheep-grazing, as at Gloddaeth (Caernarvonshire), it can still persist vegetatively (Rich 1997) but cannot flower and set seed. The Far Arnside (Westmorland) population was regularly grazed by cattle and sheep from 1973 to 1987 (I. Taylor, pers. comm.), but while the field is currently grazed by ponies and rabbits the V. spicata ssp. hybrida plants are fenced off from June to October to allow flowering and seed set (Salter in Rich 1997), although this also encourages growth of grasses (A.J.C. Malloch, pers. comm.). Watt (1964) reported that rabbits and hares grazed the ssp. spicata sites in Breckland and also noted their fondness for the inflorescences. Watt (1964) however, concluded th