BSBI Species Accounts Archive

A species of damp and wet places, including pastures, grassy fens and marshes, especially in areas with standing water in winter. This is provided in fens, meadows, pastures and scrub, primarily around the larger lakes, but occasionally also by rivers, streams and ditches. It is also able to colonise artificial habitats such as old peat diggings. It is included in the following NVC communities: M22 Juncus subnodulosus fen-meadow, S24 Phragmites australis fen and S27 Carex rostrata tall-herb fen (Rodwell 1991, 1995).

It is clear that there has been little change in the range of O. rapum- genistae, although it may have become more sparsely scattered within its area. In Scarce Plants Foley speculated that it may have retreated to coastal areas and that its decline may be climate-related; but these observations do not appear to be supported by recent records. An alternative theory could be that habitat loss is the main cause of any change or decline. O. rapum-genistae is a plant of scrubby grassland. It is difficult to find much ecological information on it - possibly because it is rare in most counties. I have seee it in U1 Festuca ovina grassland that is going over to W23 Ulex europaeus-Rubus fruticosus scrub and, ultimately, W10 Quercus robur woodland; but I have also seen it in other vegetation such as MG1 Arrhenatherum elatius grassland, perhaps. If the grassland is agriculturally improved, the scrub is cleared, or the woodland allowed to develop too far, the O. rapum-genistae disappears. Whether this sequence is typical or not, I do not know; Rodwell (1991-2000) lists no NVC communities for it.

How long O. rapum-genistae can persist at a site is a question that is in need of further investigation. Foley reports, in Scarce Plants, that it reappeared after the great storm of 1987 made clearings in some woods in southern England. In one site in Shropshire it was refound 87 years after the previous record (Shropshire Botanical Society Newsletter No. 16 (2007)) and Rumsey & Jury (1991) showed that it had persisted in one site in Lincolnshire for nearly 100 years. This suggests a ‘strategy’ of persisting in a vegetative state or in the seed bank until suitable conditions return; but, alternatively, it may simply be a good coloniser.

L. aestivum subsp. aestivum occurs in wet meadows and Willow / Alder scrub by rivers in southern England north to Oxfordshire. L. aestivum subsp. pulchellum has become established in scattered communities (usually near water) through the British Isles from the Channel Isles north to Scotland but concentrated in the South of Britain and East Anglia. Neither is represented in the National Vegetation Classification.

A sub-montane species in Britain with an altitudinal range from 90 m to 670 m (Preston et al. 2002), but usually between 150 m and 400 m (Braithwaite 1996). It was refound at 725 m in Caenlochan by Eric Meek in 2009 (Kevin Walker pers. comm.). It is assigned the following Ellenberg Indicator Values in (Hill et al. 2004): L = 8, light-loving plant, rarely found where relative illumination in summer is less than 40%; F = 5, moist site indicator, mainly on fresh soils of average dampness; R = 7; weakly acid to weakly basic conditions, never found on very acid soils; N = 5, sites of intermediate fertility; S = 0, absent from saline sites. However, regarding the L value given above, it still occasionally occurs in open woodland, and at one site in Northumberland in a quite shaded situation along an old railway line through a forestry plantation. Therefore, an L value of 6 or 7 may be more appropriate. It has no means of vegetative spread (Hill et al. 2004). It is not mentioned as a constituent species of any NVC communities in Rodwell (1992), which is not surprising due to its rarity and the fact that no vegetation samples were recorded for the NVC project from MG3c, which is one of its main modern habitats. The best available evidence of its current British ecology comes from the associated species and environmental data collected in 2008 for TPP. A preliminary examination of these data suggests it was found in the following types of vegetation: unmanaged or infrequently managed, species-rich grassland on banks and verges with other northern-montane species (neglected upland hay meadow vegetation or MG3c) appears to be the most common habitat. It also occurred in similar habitats without other northern-montane species (MG1e or MG5c). Occasionally, small populations were found in long-neglected, more rank and species-poor, bank and verge vegetation (MG1b, MG1c, M27a & MG9). In some sites the vegetation resembled a form of MG2, a sub-montane woodland glade type of vegetation that includes northern-montane species as well as woodland herbs and ferns. Some of these sites may in fact have been from W9 woodland habitats, which would not necessarily have been picked up by the survey method. One site resembles M26b, which is a species-rich and base-rich, sub-montane type of wet grassland that occurs rarely in upland hay meadows. Only one other sample was from a truly calcareous vegetation type (CG2), but several of the samples from mesotrophic grassland were on the base-rich side of mesotrophic and included other calcicole species. It appears to currently occupy different habitats in different parts of its British range. Braithwaite (2004) notes an association with intrusive rock in Berwickshire. There may be an association with intrusive rocks at some of its Teesdale locations, but this association has not been noted elsewhere. In Yorkshire and Cumbria many sites have a strong limestone influence. In Northumberland where a large proportion of its surviving populations are found, it is not strongly associated with intrusive rocks or limestone and most often occurs in unmanaged grasslands including on road verges, riverbanks and unmown banks in meadows. There is some evidence that two aspects of its main British habitats have changed over the past 100 years. Old floras frequently mention denes, thickets and woods, but most modern records are from more open habitats. Swan (1962) reports on failing to refind it in many of the old hill dene sites in Northumberland, but finding it in several new, more open, sites. Secondly, it is now found more frequently in unmanaged verge or bank vegetation compared to meadows that are still mown annually. Prior to large scale agricultural improvement it may have been more frequent in mown meadows than it is now. Its preference for meadows and lightly grazed or ungrazed situations may indicate that it is only moderately tolerant of grazing. It can tolerate annual mowing, and its relative absence from modern mown species-rich meadows may be due to the overall decline in quality of meadows due to agricultural improvement compared to verge vegetation. One or more of the following aspects of agricultural improvement may be behind its decline: artificial fertiliser applications; changes in type and/or amount of farmyard manure used on meadows; more intense spring grazing; earlier cutting dates; switch from hay-making to haylage-making; soil compaction. The following information on its preferred habitats on the continent is based on data compiled by Kevin Walker from various European floras. Most floras give hay meadows as the habitat. Interestingly in Estonia, Lithuania, Poland and southern Bohemia, wet, flooded or floodplain meadows are specifically mentioned - a habitat which it does not occupy in Britain. Several floras including eastern Germany, Czech Republic, Slovakia & Switzerland mention similar montane and sub-montane meadow vegetation to our MG3.

A low-growing perennial of dry, infertile grassland. Like many British calcicoles it appears to be physically rather than chemically restricted and is equally happy growing on moderately acid sands/gravels (e.g. dunes) as long as competition from other species is low. It grows best at low altitudes in short calcareous grassland on lime-rich soils. This includes open rides in conifer woodland in Norfolk and in the very short turf of firing ranges on Salisbury Plain.

In northern England, Scotland and the Isle of Man it occurs in grassland associated with base-rich rock outcrops, cliff-tops and sand dunes. In Scotland, for example, it grows on Old Red Sandstone sea-cliffs and on mica-schist. Populations on the Aan Islands in Western Ireland occur on deposits over limestone pavement.

Little is known about its regenerative ecology. However, the recolonisation of former plantation sites in Breckland suggests that its seedbank may be long-lived (A. Byfield, pers. comm.). A. danicus occurs in a range of NVC communities. Populations on calcareous sands and gravels in Breckland are confined to short Festuca ovina grasslands (CG2/7), especially Cladonia spp. sub-community CG7b as well as inland stands of Festuca rubra-Galium verum fixed dune grassland (SD8). Chalk populations occur in short, species-rich Bromopsis erectus (CG3) grassland (as on Newmarket Heath, Cambridgeshire). On Jurassic limestone, as at Barnack Hills and Holes in Northamptonshire, it occurs in Brachypodium pinnatum- Bromopsis erectus grassland (CG5). Inland and coastal populations in northern England and Scotland are less well studied although populations have been recorded amongst inland stands of Festuca rubra-Armeria maritima maritime grassland (MC8).

Photograph by K.J. Walker

A shade-tolerant tuberous herb usually found on chalk and limestone soils, and, like many orchids, sporadic in its appearance. In the south of England it is usually found in open deciduous woodland and scrub, but also recorded from denser shade, especially in beech woods. In woodlands it may grow with other orchids, such as Cephalanthera damasonium, Neottia nidus-avis, Orchis mascula and Platanthera chlorantha, and is included in the NVC community W12. On wood edges it grows in CG communites.

More rarely, but increasingly further north it is found in calcareous grassland, chalk-pits, limestone pavement, disused railways, spoil heaps and, rarely, unstable coastal cliffs - reaching its northerly limit on limestone slopes scree? in Cumbria (Foley & Clarke 2005). Interestingly, Irish populations are confined to open calcareous flushes and fens (M13, M13b) very unlike its habitats in England. It still survives at least one similar site on Anglesey (Cors Bodeilio) where it grows on Schoenus tussocks within species-rich fen (I. Bonner, pers. comm.). See Roberts (1958) for details of this remarkable habitat.

 The Fly Orchid is not very slow growing but it does not easily colonise new sites. This may be partly due to low seed production (Sanford 1991). The flowers are visited by wasps but pollination is often haphazard, with as few as 20% of flowers with mature seed (Foley & Clarke 2005). Flowering often starts in May in the south, though this can continue till July, especially further north.The limitations of such a finely tuned pollination mechanism may become increased, as solitary wasps are also becoming scarce, due to habitat loss (Sanford 1991). 

A biennial, occasionally annual, herb of mildly acidic to neutral, infertile (Ellenberg Value for N = 3), soils in a variety of open habitats, including pastures, hill grassland, grassy heaths, sand dunes, machair and road verges (Preston et al. 2002). The flowers are typically purple but sometimes white (Scott & Palmer 1987).

In Cornwall it grows in brown earths over serpentine, in North Hampshire on the junction of the chalk and the Reading beds, and in the New Forest on the Headon clays. On limestone it probably indicates surface leaching or the presence of non-calcareous superficial deposits (Halliday 1997). At least in Cornwall and Hampshire Carex montana grows in the same habitat. In Pembrokeshire it grows in maritime heaths overlaying Jurassic limestones.

In NW Scotland it is usually a an acid grassland plant, often growing on machair, fixed dunes and road verges where the drainage is sharp, though it does occur in a variety of other habitats, such as grassy sea-cliffs on granite and gabbro on Rum.

It is listed for the following NVC communities, CG1, CG2, CG10, CG14and MC10, but as it rarely occurs in abundance, and it was present in small quantities in a small number of quadrats collected for the NVC, these might not be particularly representative of its habitats.

In Local Change (Braithwaite et al. 2004) there is an interesting angle to its ecology, based on its distribution in 2 km squares throughout Britain. They found it to be a component of a calcareous upland vegetation, associated with Selaginella selaginoides. This is one of the more rapidly declining suites of species.

Flowers are hermaphrodite, pseudo-cleistogamous and markedly protandrous. Flowering is usually between 7-10 but can be variable especially in dry summers when populations tend to be small (Crawley 2005). The flowers are visited by humble-bees and lepidoptera, sometimes selfed (Clapham et al. 1987). In Scandinavia a decrease in populations and increasing fragmentation may have lead to a reduction in gene flow between populations and a decrease in cross-pollination within populations (Lennartsson & Oostermeijer 2001). Plants are monocarpic and regeneration is exclusively by seed. Seeds germinate in the spring but it is not known whether they have a dormancy mechanism or form a persistent seedbank.