BBS > UK Bryodiversity > Derbyshire
... with Tom Blockeel
Derbyshire is a county in the middle. Geographically it occupies a more or less central position in England, and marks the point where the Pennine uplands finally fall away to the English midlands. It is also a county hemmed in between some of the country’s major conurbations – Manchester and South Yorkshire to the north, the Potteries and the East Midlands at the sides, and Birmingham not far to the south. In the northern and western parts of the county, geological diversity and varied physical relief provide a rich and productive mix of habitats. Other parts of the county are heavily populated, with industrial development. Human exploitation has made its mark throughout. Formerly severe atmospheric pollution was injurious to the northern moors, and quarrying and mineral extraction are conducted on a massive scale. On the other hand new habitats have been created, especially through the construction of reservoirs, and these have undoubtedly enriched the flora.
Much of the north of the county lies within the Peak District National
Park. A large expanse of carboniferous limestone is exposed in the southern
part of the Park (the ‘White’ Peak), and this is Derbyshire’s
best known region botanically. To the north and east the limestone is
bounded by shale and gritstone country (the ‘Dark’ Peak).
This region includes high moorland in the north, where the Kinder-Bleaklow
uplands exceed 600m altitude. To the east, the moors are lower. Along
the Derwent valley, the gritstone forms a long series of crags, known
as ‘edges’, these being very popular with rock climbers. Further
to the east the moors fall away to the undulating Coal Measure country.
The most easterly part of the county, along the border with Nottinghamshire,
is bounded by a narrow strip of Magnesian Limestone. Low crags are exposed
here in a number of places. To the south of the Peak District and the
Coal Measure country, the land becomes increasingly low-lying. The southern
part of the county is firmly anchored in the Midlands, and is traversed
by the R. Trent. The underlying geology is varied but the bedrock is not
often exposed. Habitats here are less diverse than in the north, and are
less well recorded.
The gritstone and shale country, like Caesar’s Gaul, is divided into three parts:
The High Peak consists essentially of two large expanses of moorland plateau, Kinder Scout and Bleaklow Hill, separated by the A57 ‘Snake Pass’ road. The area is bounded to the north by the Woodhead Pass, and in the south by Edale, where shale strata are more dominant. This is the wildest part of Derbyshire and is high enough to support cloudberry Rubus chamaemorus and bearberry Arctostaphylos uva-ursi. It includes some relatively remote valleys. Ironically, however, the moorland plateau is one of the least productive habitats in the county for bryophytes, and it is possible to walk for long distances on the high desolate moorland and encounter only a handful of species. The impoverished flora may be explained by a combination of factors: the formerly severe atmospheric pollution, overgrazing in places, moorland fires, and progressive loss of woodland. Not all is gloom, however, and there are some localised habitats which retain interesting communities and a moderately rich flora. The plateau is dissected by numerous valleys, known as cloughs, through which the moorland drains. The High Peak cloughs are mostly open, with few or no trees. Their streams have a characteristic flora, including Racomitrium aciculare, Fontinalis squamosa, Hygrohypnum ochraceum, Hyocomium armoricum, Scapania undulata, Nardia compressa and, rarely, Rhynchostegium alopecuroides. In a few places Andreaea rothii occurs on irrigated grit slabs by the moorland streams. It also survives very locally on more exposed, periodically wet grit crags.
In many places in these cloughs there are runnels and seepages, and low cliffs and crags where the grit and shale beds are exposed. These low cliffs are often wet, and in places there is slightly basic seepage. They contrast with the crags of massive grit which bound parts of the high plateau. There are subtle differences in the flora of these cliffs from one location to the next, depending on aspect, geology and hydrology. Species found on many of the wet shale-grit cliffs are Fissidens osmundoides, Amphidium mougeotii, Blindia acuta, Jungermannia obovata, and more rarely Pohlia flexuosa, Isopterygiopsis pulchella, Lophozia incisa and Hygrobiella laxifolia. Anomobryum filiforme is perhaps confined to the Alport Valley. Tetrodontium brownianum, Jungermannia sphaerocarpa and Nardia compressa are characteristic of the more acidic sites, the latter being locally abundant. Palustriella commutata sometimes drapes the more basic cliffs, and Fissidens adianthoides also favours slightly base-rich sites. Species found in isolated locations where the basic influence is stronger include Anoectangium aestivum, Orthothecium intricatum and, somewhat less rarely, Jungermannia atrovirens. A number of species are more characteristic of the drier shale-grit crags. They include Pohlia cruda, Bartramia pomiformis and, very rarely, B. ithyphylla. Occasionally, where the gritstone is softer it may be colonised by Brachydontium trichodes, and more often by Seligeria recurvata. Outcrops of softer grit rock are usually small in extent, but may be less acidic than the hard gritstone, sometimes even supporting small tufts of Tortella tortuosa. This is also the habitat of Seligeria brevifolia, one of the most notable species of the High Peak moors, and confined to a single locality in Ashop Clough.
The wet cliff habitat intergrades with the runnels and flushes which often emerge along the clough sides. Like the wet cliffs, these vary in the extent of base enrichment. Some of the species of wet cliffs occur also in stony runnels, e.g. Blindia acuta, but there are additional species, notably Jungermannia exsertifolia. In the more closed flushes a variety of ‘brown’ mosses may occur, most commonly Calliergonella cuspidata but also Campylium stellatum, Palustriella commutata var. falcata, Drepanocladus exannulatus, D. revolvens and Rhizomnium pseudopunctatum, the two latter very infrequent. Riccardia multifida is sometimes present. In many springheads and flushes the association of Dicranella palustris, Bryum pseudotriquetrum and Philonotis fontana is characteristic. Sphagnum species tend to dominate the most acid flushes, sometimes with Calliergon stramineum. Remarkably, Fossombronia fimbriata was found a few years ago on bare wet peat on a flushed bank in Hollingworth Clough near Glossop. Isolated basic flushes support Plagiomnium elatum, Trichocolea tomentella and Drepanocladus cossonii. The more base-tolerant Sphagna are rare; S. warnstorfii has one station, S. teres several.
Sphagnum species are sometimes luxuriant on moist heathy banks on the clough sides, especially those with a northerly aspect. S. subnitens may form large clumps, and S. russowii and S. girgensohnii occur locally.
Mineral soil is often exposed on the steeper slopes. Oligotrichum hercynicum and Ditrichum heteromallum are frequent, at least in the upper parts of the cloughs. Polytrichum alpinum has a few localities on turfy banks. Of special interest is the occurrence of Jungermannia caespticia on moist gritty soil, so far recorded from three places. Banks of fine acid shale are exposed locally, and are a characteristic habitat for Dicranella cerviculata. Discelium nudum occurs on banks of decomposed shale/clay, but is rather rare. Entosthodon obtusus is even more rare, being known at present only from one site in the lower part of Hollingworth Clough. Peaty banks, especially around the moorland edges and in rough pasture, very occasionally have Nardia geoscyphus and Lophozia bicrenata.
Block litter is not common on the high moors, but occasionally occurs below gritstone crags, often in hollows caused by slumping of rock over unstable shale. A classic example is at Alport Castle, where a massive detached pinnacle has slipped downslope, with block scree accumulating between it and the parent crag. Unvegetated blocky ground on drier (especially south-facing) slopes, including that at Alport, may be rather poor in species, although Barbilophozia atlantica and/or B. floerkei are usually present. On north-facing slopes, or where the block litter is vegetated, there may be a rather richer flora. Examples occur on the western slopes of Kinder Scout, in the Westend valley, and in Grindsbrook Clough. Mylia taylorii occurs in several localities where the block litter is moist with accumulations of peat, more rarely associated with Kurzia trichoclados. Racomitrium lanuginosum and R. fasciculare are widespread but nearly always sparse. Many species in this habitat are restricted to a few isolated sites (sometimes only one). They include Andreaea rupestris, Bazzania trilobata, Barbilophozia barbata, Lophozia sudetica and Anastrophyllum minutum. Lepidozia pearsonii has recently been found at a couple of localities on blocky ground. Occasional fragments of softer, slightly basic rock sometimes occur in the block litter, as they do in the cloughs, supporting small quantities of Tortella tortuosa and Frullania tamarisci, and patches of Seligeria recurvata.
The peat bogs of the High Peak are badly degraded because of the severe atmospheric pollution which blew onto the moors during much of the nineteenth and twentieth centuries. Fragments survive in boggy hollows and flushes, but the characteristic hepatics of healthy Sphagnum bog are no longer present. Sphagnum capillifolium is very rare, leaving S. papillosum, S. denticulatum, S. subnitens, S. fallax and S. cuspidatum as the prevailing species. Associates may included Campylopus flexuosus, Drepanocladus fluitans and Calliergon stramineum, though the latter is more often found in Juncus flushes and in moist peaty turf.
Although the open moorland may be desolate and yields its treasures reluctantly, there are some rare delights to reward the persistent searcher. These include Splachnum sphaericum and Tetraplodon mnioides on sheep dung and bones. Both of these are rare but are still present, both having been recorded recently on the northern slopes of Kinder Scout. Blue Calypogeia, C. azurea, is another little gem, usually on bare peaty grit.
Reservoirs – The Ladybower Reservoir complex is the largest in Derbyshire. Howden, Derwent and Ladybower Reservoirs successively occupy 9 km of the Upper Derwent Valley, and a separate arm of Ladybower extends some 4 km along the R. Ashop in the Woodlands Valley. The exposed margins have, in some summers, large expanses of peaty-gritty soil, and in places gleyed banks. Many calcifuge species occur in this temporary habitat, including sometimes Discelium nudum in extensive stands. Other recorded species are Atrichum crispum, Pseudephemerum nitidum, Dicranella rufescens, Pohlia camptotrachela, P. bulbifera, Hypnum lindbergii and Fossombronia wondraczekii. Some of these species also occur at Kinder Reservoir on the western side of Kinder Scout. The Laybower complex is bordered by zones of planted woodland, including conifer plantations. Diplophyllum obtusifolium has been found recently here on a bank by a forest road on the western arm of Ladybower Reservoir.
A notable feature of the reservoirs is the flora of the mortared gritstone walls. These are the principal habitat in Derbyshire for Ptychomitrium polyphyllum. Racomitrium lanuginosum and R. heterostichum also occur occasionally on these walls, and those by Kinder Reservoir have Grimmia donniana and Racomitrium sudeticum.
Edale and Bretton Clough – The Kinder/Bleaklow uplands give way southwards to a landscape domianted by shale strata. This region includes parts of Edale, with the unstable hillside of Mam Tor, and Bretton Clough. These are less rich in general than the High Peak moors, because of the limited exposures of harder rock. However the small piece of woodland in Abney Cough has a moderately rich flora, including Tetrodontium brownianum, Amphidium mougeotii, Heterocladium heteropterum and Hookeria lucens.
The principal moors in the Buxton district are in the Goyt Valley and at Combs Moss. These moors generally lack the pockets of base-enrichment which give the High Peak its greater diversity of species. Doubtless also the two reservoirs which occupy the floor of the Goyt Valley have destroyed some good habitat. Nevertheless these moors share many of the characteristic species of the High Peak. Discelium nudum occurs at the head of the Goyt Valley, and Odontoschisma denudatum is known from Park Wood in the lower part of the valley (this site being within the modern administrative county but historically in Cheshire (v.-c. 58). Diphyscium foliosum has been recorded from the v.-c. 58 side of the valley, but is currently unknown elsewhere in Derbyshire.
The margins of Fernilee Reservoir, the lower of the two reservoirs in the Goyt Valley, have areas of peaty sand exposed in late summer, with a rather rich flora including Archidium alternifolium, Ephemerum serratum var serratum, Pohlia camptotrachela, P. bulbifera, P. drummondii, Hypnum lindbergii and Fossombronia wondraczekii.
Combs Moss is not fully explored, but there is a good area of block litter below the escarpment at Castle Naze, supporting Mylia talyorii and Scapania gracilis. Combs Reservoir nearby is a long-known station for Physcomitrium sphaericum. Also present here are Archidium alternifolium, Ephemerum serratum var. serratum, Weissia rostellata, Aphanorhegma patens and Hypnum lindbergii.
From its headwaters in the High Peak the R. Derwent flows in a more or less southerly direction through the heart of the county to the city of Derby. From Ladybower Reservoir in the north to Matlock and beyond in the south it cuts a broad valley through the millstone grit (and also through the Carboniferous Limestone at Matlock). Large stretches of the eastern side of the main valley are flanked by gritstone crags, known as edges, rising to 450 m at Stanage Edge. These edges are backed by expanses of gritstone moorland which fall away gently to the east, to be succeeded eventually by the Coal Measures. Southwards the edges decrease in both altitude and extent, but patches of moorland persist to the Matlock region. There is also an expanse of gritstone moor to the west of the R. Derwent, at Stanton.
The Eastern moors are generally lower than the High Peak and do not have the same diversity of habitat. The moorland flora is therefore not so rich, lacking many of the more northerly species and some of the basiphile species. However Nardia compressa and Oligotrichum hercynicum occur sparsely southwards at least to the Big Moor district near Baslow. Atrichum crispum is widespread in the latter district. A noteworthy feature of the gritstone edges is the widespread occurrence of Leptodontium flexifolium on thin peaty soil, especially over rocks and boulders. Ptilidium ciliare is also widespread, though usually sparse. The eastern moors have some areas of peat bog, but as in the High Peak these are generally degraded. Sphagnum papillosum and S. subnitens occur sparsely; S. capillifolium is very rare. However Cladopodiella fluitans has a few localities, for example at Hipper Sick. Mylia anomala was recorded at the latter site in 1972 but has not been refound since. Drepanocladus fluitans and Calliergon stramineum occur in boggy flushes.
The exposed crags of the edges are themselves almost devoid of bryophytes, being very popular with rock climbers. Of much greater interest bryologically along the edges are the rocky streams which fall from the moors, and the blocks of deciduous woodland which are found in some parts. The best of the woodlands are
There are also some interesting gritstone woodlands in the more southerly parts of the Derwent valley, for example in the Beeley district, at Hall Dale and at Shining Cliff.
The best of these woods contain block litter of millstone grit with a characteristic calcifuge flora. Luxuriant forms of Barbilophozia atlantica are often plentiful on the boulders, sometimes with B. attenuata. The best woods also have some or all of the following on the grit boulders: Dicranum fuscescens, Tritomaria exsectiformis, Cephalozia lunulifolia, Scapania gracilis and S. nemorea. More common calcifuge species also occur, for example Lepidozia reptans, Dicranum majus, Campylopus flexuosus, Isothecium myosuroides and Plagiothecium undulatum. Other species are unaccountably rare, notably Rhytidiadelphus loreus, with only two sites. Leucobryum is also rare, the best locality being a well-known one in Padley Wood. Bazzania trilobata occurs sparsely at Ladybower Wood and Gardom’s Edge, and Dicranodontium denudatam is known only from Shining Cliff Wood. On some of the lightly shaded crags there are a few sites for Cynodontium bruntonii. There is additional diversity along the streams. Jungeramnnia paroica has a few sites on thin soil on grit rocks along the stream edges. Racomitrium aciculare is common, Heterocladium heteropterum widespread, Trichostomum tenuirostre and Metzgeria conjugata rare. There are a few scattered sites for Lejeunea lamacerina and L. cavifolia, and two sites for Fissidens rivularis (in Shining Cliff Wood and Smeltingmill Wood). Brachydontium trichodes occurs by the Beeley Brook, and Blepharostoma trichophyllum in Padley Wood. The more sheltered stream banks occasionally have good patches of Hookeria lucens.
There is a particularly interesting site along the upper reaches of the Bar Brook, at the northern side of Gardom’s Edge by the A621 road. Isothecium holtii has an isolated site here, and Scapania lingulata is recorded from a grit boulder. There is some slight basic seepage on the stream banks, presumably from the overlying drift. This may explain the presence of Barbilophozia barbata and Tritomaria quinquedentata. More remarkably, there is a small population of Scapania cuspiduligera on the side of one rock.
Another special site is on the banks of the R. Derwent at Coppice Wood, Padley. There are some large grit boulders on the river bank here, supporting a very sparse population of Lophocolea fragrans, growing with Lejeunea lamacerina. This is the only county site for L. fragrans, and a very isolated one.
Schistostega pennata has several sites in sandy rock crevices on the Millstone Grit in the middle Derwent Valley, for example at Stanton Moor.
The banks of the Derwent towards Matlock have a moderately well-developed riparian flora on the trunks and roots of riverside trees. Orthotrichum sprucei occurs sparsely, and Syntrichia latifolia and Leskea polycarpa more plentifully. Fissidens crassipes is widespread, but more often on stones than tree roots. The river in some places has exposed banks of gritty clay soil, and Discelium nudum occurs here, albeit rarely, in a more pastoral setting than at its moorland sites.
The Coal Measures succeed the Millstone Grit and occupy a large portion of the county to the east of the Peak District uplands, falling away from the eastern moors to the ‘M1 corridor’ in the east of the county. Coal was mined extensively in the lower-lying regions, and although mining has now almost ceased, the eastern Coal Measures are extensively industrialised and at times present a bleak landscape. Westwards the countryside is more attractive, with rolling ridge and valley terrain merging with the moorland fringes. This is especially so to the west of Chesterfield, but the Moss Valley to the south of Sheffield is also attractive.
Botanically the Coal Measures do not compare very favourably with the Peak District uplands. The reasons are not far to seek: the gentler terrain, the absence of massive rock outcrops, the more uniformly acid nature of the ground, and the more intensive cultivation and industrialisation. Against this background, there are three habitats of particular bryological note:
Stream valleys, particularly in the hillier parts, have some of the species of the gritstone country, including Heterocladium heteropterum, Thamnobryum alopecurum, Brachythecium plumosum, Hyocomium armoricum, Plagiochila porelloides and Jungermannia pumila, but most of these quickly peter out towards the lower ground. Chiloscyphus polyanthus is particularly characteristic of these Coal Measure streams, and Eurhynchium speciosum is recorded from a few sites. The Oldhay Brook near Totley has a regularly fruiting population of Fontinalis squamosa. The woodland flora is generally calcifuge and rather poor. Most remarkable is an isolated population of Fissidens celticus in the Moss Valley. Dicranum tauricum is a rather common epiphyte, and recently Orthotrichum pulchellum and Ulota phyllantha have become more widespread with improvements in air quality. Cryphaea heteromalla and Orthotrichum tenellum have also been recorded from Coal Measure valleys. Good examples of such valleys are found in the Totley, Holmesfield and Holymoorside districts, and further south at Ogston.
The Coal Measures are widely cultivated and stubble fields have a characteristic bryophyte flora which includes Dicranella staphylina, Ditrichum cylindricum, Tortula truncata, Bryum klinggraeffii and B. violaceum. Other species which occur less frequently are Ephemerum serratum and the liverworts Riccia glauca, R. sorocarpa and Fossombronia wondraczekii. Acaulon muticum has been recorded at one site in the Moss valley. In some fields the substratum consists of heavy clay, and this habitat is notable for Didymodon tomaculosus. This species occurs in some five localities from Totley in the west to Pebley in the east. Associates on clay include Pseudephemerum nitidum, and very rarely Weissia rostellata and W. brachycarpa var. brachycarpa.
There are two principal reservoir developments on the Coal Measures, at Linacre and Ogston. Ogston Reservoir has large expanses of organic mud in dry summers with an abundance of Riccia cavernosa and Aphanorhegma patens. The upper reservoir at Linacre also has Aphanorhegma patens, but there are patches of more sandy ground where Archidium alternifolium and Ephemerum sessile have been recorded.
The Carboniferous Limestone forms a well-defined region, extending from Castleton in the north to Dove Dale in the south-west and Matlock in the south-east. It is an undulating plateau dissected by deep valleys, collectively known as the Derbyshire Dales. These dales are botanically rich, and are well-known for northern plants such as globeflower Trollius europaeus, Jacob’s Ladder Polemonium caeruleum, and mossy saxifrage Saxifraga hypmoides, along with southern plants such as dropwort Filipendula vulgaris and stemless thistle Cirsium acaule. The limestone is locally of high quality, and mineral veins occur frequently. The White Peak, especially in the vicinity of Buxton, is therefore one of the UK’s most important quarrying regions. The dales also have local intrusions of igneous rock, though these exposures are mostly small in extent. They may, however, be quite significant bryologically.
Aspect is important in the dales in determining the composition of the vegetation. Skeletal soil on stony ground and earthy rock ledges on open dale sides support some very distinctive communities. These are mostly found on seasonally dry and sunny slopes. Many of the species are ephemeral and are most evident in autumn, winter and spring. They include Microbryum rectum, M. davallianum, Tortula protobryoides, T. lanceola, T. modica, Weissia brachycarpa var. obliqua, Encalypta vulgaris, Funaria muhlenbergii, Entosthodon fascicularis and Riccia sorocarpa. Some perennials also occur in this habitat: Ditrichum flexicaule, Didymodon ferrugineus, Pleurochaete squarrosa and Targionia hypophylla, the latter always on thin soil on rock outcrops. Reboulia hemisphaerica is rather common, but is not confined to the drier slopes. There are isolated localities on sunny crags for Tortella nitida and Bryum canariense. Short grazed turf generally occurs on the sunnier dale sides and in disused quarries and workings, but is less extensive than in the past. Campyliadelphus chrysophyllus is widespread, but Thuidium philibertii is rare, and Entodon concinnus unaccountably so.
North-facing slopes and crags often contrast strongly with their south-facing counterparts. Earthy ledges are moister and the soil is often leached, to the extent that sparse limestone heath is occasionally developed. Where there is bare soil on rock ledges, Tritomaria quinquedentata, Lophozia excisa, Campylopus fragilis and Plagiobryum zierii may sometimes occur. Some north-facing crags may accumulate deep humus and, especially where lightly shaded, may support dense turfs of Dicranum majus, D. scoparium, and robust pleurocarps such as Hylocomium splendens and Rhytidiadelphus triquetrus. Ptilidium ciliare sometimes occurs as isolated stems in mixture. Moist stony grassland also supports plentiful H. splendens and R. triquetrus, more rarely with Dicranum bonjeanii. Climacium dendroides is characteristic of moist grassland at the base of rocks and walls. Of particular interest in limestone grassland is the occurrence in a few places of the ‘Atlantic’ moss Breutelia chrsyocoma, sometimes in short turf but also on rock ledges.
Limestone scree occurs in many of the dales. Consolidated scree is the characteristic habitat of Rhytidium rugosum, which occurs at several sites but is particularly fine in the lower part of Monks Dale. Racomitrium lanuginosum occurs very locally in this habitat, and Barbilophozia barbata has been found sparsely in the upper part of Cressbrook Dale. Consolidated scree shares many species with stony grassland and blocky ground. Homalothecium lutescens is widespread, and sometimes occurs in an appressed form closely attached to the rock. Frullania tamarisci occurs locally in scree and on stony banks.
Sheltered limestone rocks in the wooded dales and on more open sites on the more northerly slopes often support a profusion of calcicolous bryophytes, including conspicuous species: Tortella tortuosa, Mnium stellare, Plagiomnium cuspidatum, P. undulatum, Neckera crispa, N. complanata, Thamnobryum alopecurum, Anomodon viticulosus, Eurhynchium crassinervium, E. striatum, Ctenidium molluscum, Apometzgeria pubescens, Plagiochila porelloides, Porella platyphylla and P. cordaeana. Hylocomium brevirostre is very rare. Bare, often vertical rock faces where there is sufficient moisture support Cololejeunea calcarea, Leiocolea alpestris, Scapania aspera, Preissia quadrata, Gymnostomum aeruginosum, Seligeria acutifolia, S. pusilla, S. donniana and (very sparsely) S. trifaria. Amblystegium confervoides appears to be rare, while Orthothecium intricatum is usually found in rock crevices. Rhynchostegiella teneriffae is very local on wet rocks. In some of the dales there are accretions of tufa (travertine), and this is a highly characteristic habitat for Gymnostomum calcareum. Platydictya jungermannioides also occurs, rarely, on tufa and at the entrance to wet holes and fissures. Conardia compacta occurs in a cave in Dove Dale.
Wooded limestone crags, especially the more northerly ones, support a few species of a montane character, notably Plagiopus oederianus and Mnium thomsonii, but these are rare. Pedinophyllum interruptum is possibly confined to the crags and cliffs of Chee Dale. A notable species of sheltered but dry crags is Brachythecium appleyardiae, which is widely distributed in at least eight localities. It is particularly characteristic of dry ledges at the base of crags, where there is little competition from other species. Bryophytes occurring in warmer woodland sites include Eurhynchium striatulum, Taxiphyllum wissgrillii, Marchesinia mackaii and Cololejeunea rossettiana, but all of these are rare.
Old limestone walls are often clothed in bryophytes, and some species are commoner on walls than elsewhere. Three of the five recent records of Leucodon sciuroides are from old walls, and Syntrichia ruralis is most often found in this habitat. Ditrichum flexicaule favours old, broken walls, but also occurs on stony ground.
Intrusions of igneous rock in the limestone dales include basalt. The exposures are mostly small in extent. There are significant outcrops, partly quarried, in Tideswell Dale, where Ptychomitrium polyphyllum has possibly its only site on natural rock in Derbyshire. A restricted and solitary population of Grimmia laevigata occurs on a small outcrop at the northern end of Dam Dale near Peak Forest. Another exposure, in Cressbrook Dale, has Schistidium pruinosum. Slightly less rare are Bartramia pomiformis and Racomitrium heterostichum. Curiously, Racomitrium aciculare occurs on several of these dry outcrops.
The limestone plateau has deposits of silica in places, and the major deposits have been extracted. Old pits at Bees Nest near Brassington are the only recorded site for Fossombronia incurva in Derbyshire. Bryoerythrophyllum ferruginascens also occurs here. Old lead workings are common on the limestone in Derbyshire, but do not appear to have a particularly distinctive bryophyte flora. However B. ferruginascens occurs in a few places and Sanionia uncinata has been found in turf on old spoil heaps.
As elsewhere in Derbyshire, epiphytic species in the limestone dales have recovered in recent years with reductions in SO2 pollution. Orthotrichum pulchellum, Ulota phyllantha, Cryphaea heteromalla and Metzgeria fruticulosa occur widely, though mostly in small quantity. However Syntrichia laevipila, Orthotrichum lyellii, O. striatum, O. tenellum, Zygodon comoideus and Radula complanata remain rare, though all have been recorded recently. A particular feature of some localities, especially in the Via Gellia and near Topley Pike, is the presence of Pylaisia polyantha, sometimes in remarkable abundance. As the best sites are near active limestone quarry complexes, it is possible that this species benefits from limestone dust in the atmosphere. Sanionia uncinata is also a characteristic epiphyte in some dales, especially in the Wye Valley.
Quarries in all stages of operation and abandonment occur throughout the White Peak. Bryologically, they are most interesting when disused but not overgrown. Bare soil on rock ledges and on quarry floors sometimes support distinctive communities. Earthy ledges are the usual habitat in the county for Aloina aloides. Bare calcareous ground occasionally produces Leiocolea badensis and very rarely Lophozia perssonii. Distichium inclinatum occurs in the vicinity of Topley Pike Quarry. Preissia quadrata has colonised old damp quarry faces in one or two places. Some of these species also occur in old railway cuttings, and Distichium capillaceum is known from a cutting at Blake Moor.
The Magnesian is a dolomitic limestone of Permian age. Geographically and geologically it is quite separate from the Carboniferous Limestone. It is low-lying, but is exposed in a few places as low crags and outcrops. Because of its geographical position overlying the Coal Measures, it is adjacent to many of the former mining villages of East Derbyshire. Much of the ground is given over to cultivation and very little natural grassland survives. There are several large blocks of woodland, but all of them have been felled at times during the 20th century, though some small areas are still of interest.
The best surviving fragments of grassland are at Markland Grips near Clowne and in Pleasley Vale near Mansfield. The former is not fully explored. The latter has Weissia longifolia var. angustifolia and Ephemerum recurvifolium on thin soil over the limestone. Microbryum rectum also occurs at a few sites in this habitat. One of these is in a tiny fragment of grassland in the cemetery at Whitwell, where (more remarkably) Rhynchostegium megapolitanum also occurs. Microbryum floerkeanum has been found recently in a stubble field near Whitwell and may occur more widely.
Given the history of exploitation in this part of Derbyshire, and the formerly high levels of pollution from the mining industry, a surprisingly rich flora persists on some of the limestone outcrops, especially those in wooded or sheltered sites. Most noteworthy is the occurrence on the low crags on the northern side of Whitwell Wood of Marchesinia mackaii and (sparsely) Apometzgeria pubescens. Other species on shaded limestone include Distichium capillaceum, Tortula marginata, Gymnostomum calcareum, Leiocolea alpestris (in a very small form), Jungermannia atrovirens, Campylophyllum calcareum, Conardia compacta and Taxiphyllum wissgrillii. Some of these are confined to single locations. Hennediella macrophylla occurs on a path on the limestone at Nether Langwith. There are springs with Palustriella commutata at Markland Grips and at the northern end of Whitwell Wood. Trichocolea tomentella occurs over a very small area at the latter site.
The limestone is actively quarried near Cresswell and at Bolsover Moor. Armstrong Quarry, a disused quarry near Darfoulds in the extreme north-east of the county, contains alkaline waste with a large population of Tortula cernua, and also Lophozia perssonii and Aloina ambigua. The future of this interesting site is at present uncertain.
Carsington Reservoir SK250510 is a newly constructed reservoir on the edge of the White Peak south-west of Wirksworth. The bed of the reservoir is on clay overlying carboniferous grits. The margins of the reservoirs have already developed an interesting flora, including Didymodon tomaculosus, Weissia rostellata, Aphanorhegma patens, Riccia cavernosa and Fossombronia wondraczekii. Some of these species, including the Didymodon and Weissia, were probably present in the region before the construction of the reservoir.
Calke Park SK367225 is one of several parkland estates in south Derbyshire, and is now owned by the National Trust. There is an outlier of limestone in this region, and there are old quarries at Ticknall Limeyards SK361239 (also National Trust), now mostly recolonised by woodland. The limestone is not much in evidence in Calke Park, although Microbryum davallianum and Ephemerum recurvifolium have been recorded recently on a grassy bank near the Hall. The parkland contains some ancient oak trees, with a little Isothecium myosuroides. Physcomitrium pyriforme has also been recorded. Tortula marginata occurs on walls at the church in the Park, and also in Ticknall Limeyards. Sudbury Hall SK157320 is another National Trust property. Riccia fluitans was recorded in the lake here in 1988.
Carvers Rocks SK330227 is a Derbyshire Wildlife Trust Reserve on an outcrop of Millstone Grit at the southern end of Foremark Reservoir. It has one of the few remaining areas of heath in south Derbyshire, and there is a small mire with some Sphagnum spp. (including S. flexuosum). Schistostega pennata occurs on a grit crag. Hypnum lindbergii and Plagiothecium latebricola were recorded in 1972.
The banks of the R. Trent are not generally rich in
bryophytes but Syntrichia latifolia and Leskea polycarpa
occur. Scleropodium cespitans is known from Anchor Church