BSBI Species Accounts ArchiveCampanula patula
Thu, 08/12/2010 - 17:45 | 
markd
Name: Campanula patula L., Spreading Bellflower.
Several subspecies occur in continental Europe; British plants are ssp. patula (Tutin et al. 1976).
Chromosome No.: 2n = 20 (Stace 2010).
Photograph: A.J. Lockton
Its distribution in Britain is very unusual, being centred on the southern parts of the Welsh Marches, from Shrewsbury in the north to Monmouth in the south. Elsewhere there are only scattered populations, which are usually short-lived, and many of these are considered to be garden escapes. It occurs throughout Europe and much of Asia, but is rare in the west, making the British populations noticeably isolated.
Click on the map to view full-size on the BSBI Maps Scheme website.
- Origin: generally considered to be a native plant, at least in England and Wales. The first record was at Effaton (Adforton) in Herefordshire, in 1666, by Christopher Merrett (Clarke 1900; Merrett 1666).
- Rarity: it would currently be ranked as Nationally Scarce, based on the number of current records shown on the Maps Scheme.
- Threat: It has declined dramatically in recent decades, and is now listed as Endangered (Cheffings & Farrell 2005).
- Conservation: it is a UK BAP priority species. One county currently has it listed it as an axiophyte (Durham) - but this is surely a mistake. It has no obvious association with high quality habitat.
Day (in Stewart et al. 1994) reports that it is a biennial plant, reproducing by seed, and suggests that it requires disturbed and sunny sites for germination. He describes it as a plant of open woodland and reports that it is seldom found far from areas of ancient woodland. Sinker et al. (1985) describe its habitat in Shropshire as grassy banks by rivers and roads, edges of fields, open woodland or scrub and green lanes. Crawley (2005) considers it a casual in sown grasslands in Berkshire. In Europe and Asia it is most commonly a plant of hay fields. Rodwell (1991-2000) does not list it as a component of any NVC community.
Photograph: A.J. Lockton
The status of Campanula patula in Britain is, in truth, something of a mystery. The disjunct range could be caused by one of two likely mechanisms: either it was once much more widespread and has since become rare; or it arrived in the Welsh Marches as the result of a long-distance dispersal event. The former would make it a truly native species, but it seems quite unlikely. If the latter is true, then it is most probable that the ‘dispersal event’ was facilitated by humans - in which case it may be best described as an archaeophyte in this country. Plants on the edge of their range often behave in unpredictable ways. Only a detailed genetic study could resolve this question, but ecologists could usefully identify a semi-natural vegetation community for it, if it is to be managed sustainably in future.
- Crawley, M.J. 2005. The Flora of Berkshire. Brambleby Books, Harpenden.
- Merrett, C. 1666. Pinax rerum Naturalium Britannicum.
- Sinker, C.A., Packham, J.R., Trueman, I.C., Oswald, P.H., Perring, F.H. & Prestwood, W.V. 1985. Ecological Flora of the Shropshire Region. Shropshire Trust for Nature Conservation, Shrewsbury.
- Webster, H. 2007. An assessment of the current status and distribution of Campanula patula L. (Campanulaceae), Spreading Bellflower, in Britain and observations on its decline. MSc dissertation, University of Birmingham.
Tags: Woodland
Melampyrum sylvaticum
Thu, 08/12/2010 - 00:54 | markd
Although the name Melampyrum sylvaticum L. is uncontroversial (Stace 1997), in the past its identification in Britain has been much confused with that of M. pratense (Rumsey in Stewart et al. 1994; Rich et al. 1998). A key feature is the downturned end to the lower lip of the corolla (flower), as seen in the photograph here. The size of the plant and the flower colour are not reliable diagnostic features (Rich & Jermy 1998).
Chromosome No.: 2n = 18 (Stace 2010).
Small Cow-wheat is endemic to Europe, occurring in the Alps and mountainous regions in southern Europe, but mainly in Scandinavia and the Baltic States eastwards into Russia (Rich et al. 1998).
In the British Isles it is found in the mountains of Scotland and Northern Ireland and was formerly present in Yorkshire, Co. Durham and North Wales, but is believed to be extinct there now.
Click on the map to view full-size on the BSBI Maps Scheme website.
- Origin: native.
- Rarity: Nationally Scarce in Britain, but all known populations are in Scotland. It is extinct in England and Wales, and rare in Ireland.
- Threat: in 1994 (in Stewart et al.) Rumsey described M. sylvaticum as over-recorded. Rich & Sydes (2000) resurveyed known sites and also concluded that there was a severe decline and considerable over-recording. However, Rumsey (in Preston et al. 2002) now describes it as almost certainly under-recorded, a view that is echoed by Cheffings & Farrell (2005), who classified it as Endangered. Dalrymple (2007) argues that it should be listed as Vulnerable.
- Conservation: it is a Priority species under the UK Biodiversity Action Plan and much work has been undertaken to further its conservation, including introductions to new sites, mixing of seeds from disparate populations (Dalrymple 2007); and apparently there are even proposals to translocate ants to assist in the dispersal of seeds (S. Dalrymple, pers. comm.)
Despite all of the study of this species, surprisingly little is known about its reproductive ecology. It was believed to be pollinated by bees (e.g. Rumsey in Stewart et al. 1994) and for the seeds to be dispersed by ants (e.g. Rich & Sydes 2000) but Dalrymple (2007) asserts that neither of these have been observed in Britain. It can be self-fertile.
Melampyrum sylvaticum is considered a woodland plant that occurs in light shade (up to 50%) and high humidity, always close to water (ibid.). It is often found on rock ledges in mountain valleys, but some of the largest populations occur in woodland by lakes (e.g. at Loch Ossian). Rich et al. (2000) state that it occurs in herb-rich places in W11 woodland, and Dalrymple (op. cit.) adds H17, H18, W17 and U16 communities.
The assertion that it is under-recorded is based on a few recent discoveries of new sites. Speculative surveys of potentially promising areas, especially in the mountains of western Scotland, might help to confirm that. Sites might typically be rock ledges in high valleys. All new records need to be properly documented - a good photograph is sufficient to confirm the identification, but it is not a protected species (except in Northern Ireland) and specimens may be taken if the population is sufficiently large. There is no obvious need for secrecy.
When introductions and other conservation work is carried out, it should be fully documented even if it is unsuccessful. A practical mechanism for this is www.conservationevidence.com.
- Dalrymple, S.E. 2007. Biological Flora of the British Isles: Melampyrum sylvaticum L. Journal of Ecology 95, 583-597.
- Rich, T.C.G., Fitzgerald, R. & Sydes, C. 1998. Distribution and ecology of Small Cow-wheat (Melampyrum sylvaticum L.; Scrophulariaceae) in the British Isles. Botanical Journal of Scotland 50, 29-46.
- Rich, T.C.G. & Sydes, C. 2000. Recording and the declines of the Nationally Scarce plants Ajuga pyramidalis L. and Melampyrum sylvaticum L. Watsonia 23, 293-197.
Tags: Woodland
Paris quadrifolia
Tue, 08/10/2010 - 17:36 | markd
Common name: Herb Paris.
It is unlikely to be confused with any other species in the British flora (Tutin et al. 1980; Stace 1997). The only other member of this genus that occurs in Europe is P. incompleta (Jacqemyn, Brys & Hutchings 2008).
Chromosome No.: 2n = 60 (tetraploid) (Stace 2010) .
It is common throughout northern Europe and Asia as far as Siberia, but is rare in the Mediterranean region (Tutin et al. 1980; Sell & Murrell 1996). In Britain it is widespread but with a somewhat scattered distribution. It is absent from the Northern Isles, the Outer Hebrides and Ireland, and it is very scarce in westernmost parts (Preston, Pearman & Dines 2002). Its highest recorded altitude in Britain is 360 m, at Great Asby Scar (v.c. 69) and Garrigill (v.c. 70) (Pearman 2004).
Click on the map to view full-size on the BSBI Maps Scheme website.
Paris quadrifolia is too widespread to have any official rarity status and, although the New Atlas (ibid.) gives it a Change Index of -0.68, it is not considered threatened. In Scotland, however, it could be described as a rare plant.
Most authors simply describe P. quadrifolia as a woodland plant and leave it at that. Flora Europaea (Tutin et al. 1980) says: ‘woods and other damp or shady places.’ Stace (op. cit.) states: in moist woods on calcareous soils. Jacqemyn, Brys & Hutchings (2008) list it as a constituent of the NVC communities W8 and W9, sometimes occurring in W12, W7 and W2. Crawley (2005) considers it to be a plant of sheltered oak/ash woods in Berkshire, and gives its NVC type as W12 Fagus sylvatica - Mercurialis perennis woodland, but Jacquemyn et al. (op. cit.) report it being found in Alnus glutinosa woodland there. It is widely considered to be an Ancient Woodland Indicator (e.g. Rackham 1986), but Taylor (in Preston, Pearman & Dines 2002) offers a slightly different view. He describes it as favouring the open stages of the coppice cycle and occurring in grikes on limestone pavement. He considers that it readily spreads into secondary woodland; a view echoed by Jacquemyn et al. (2008).
One unanswered question about P. quadrifolia is how it has managed to disperse so widely in Britain. Most reproduction is by vegetative means, and the seeds are believed not to travel far. But with such a specialised habitat requirement, it clearly has to cross inhospitable terrain to reach suitable locations. This suggests that it may have greater powers of dispersal than is currently known. Whether it is really declining or not is unclear from the evidence. It does not appear to have contracted in range, and the 10 km data may not be sufficiently detailed to warrant an analysis within its range.
- Crawley, M.J. 2005. The Flora of Berkshire. Brambleby Books, Harpenden.
- Jacquemyn, H., Brys, R. & Hutchings, M.J. 2008. Biological Flora of the British Isles: Paris quadrifolia L. Journal of Ecology 96, 833-844.
- Rackham O. 1986. A History of the Countryside. Phoenix, London.
Lockton, A.J. (date accessed). Species account: Paris quadrifolia. Botanical Society of the British Isles, www.bsbi.org.uk.
Tags: Woodland
Aconitum napellus
Tue, 07/20/2010 - 11:51 | admin
Monk’s-hood, Aconitum napellus L., is a very variable species, with numerous subspecies described in Europe (Tutin et al. 1993). British plants are A. napellus ssp. napellus which has, in the past, sometimes been treated as a separate species, A. anglicum Stapf.
Chromosome No.: 2n = 32 (Stace 2010).
Photograph: M. Duffell
Most of the Monk’s-hood plants in Britain are believed to be of garden origin, and these are usually not A. napellus, but a hybrid with the closely-related southern European species A. variegatum. The cross is called A. x cammarum, Hybrid (or Garden) Monk’s-hood. Separating true Monk’s-hood from Garden Monk’s-hood is not always easy, especially as the former is sometimes also cultivated in gardens. A useful key to their identification is given by Silverside in Plant Crib. It can be downloaded here:-gt;> Silverside’s Key pdf, 183 kb).
Aconitum napellus ssp. napellus is thought to be restricted to SW Britain but it is occasionally introduced elsewhere in the British Isles. However, the Maps Scheme maps show the distribution of A. napellus sens. lat., which includes A. x cammarum. Outside Britain, A. napellus ssp. napellus is sometimes described as occurring in parts of France, but this is uncertain (Stace, 1997).
Click on the map to view full-size on the BSBI Maps Scheme website.
Origin: almost certainly native. Although it has always been cultivated as a powerful medicinal herb, there are pollen records that show that an Aconitum species was present in Britain many thousands of years ago (Brayshay & Dinnin, 1999).
Rarity: the native plant is thought to be Nationally Scarce in Britain (Stewart, Pearman & Preston 1994) as it is probably present in fewer than 100 hectads (10 km squares). However, it is considered to be over-recorded in the Welsh Marches (Preston, Pearman & Dines 2002) so possibly it is rarer than that.
Threat: given the quality of the records, it is impossible to give a good estimation of its threat status, but in the New Atlas it is given a Change Index of +1.42 whereas Cheffings & Farrell (2005) put it on their ‘Waiting List’ pending taxonomic studies.
Conservation: no county recorder has yet listed it as an axiophyte, possibly because of the confusion between the taxa. However, its ecology (see below) suggests that native populations should indeed be considered of conservation importance.
It is a tuberous perennial occurring in shady places by streams particularly in wet alder, hazel and oak woodland, usually referable to W6 Alnus glutinosa woodland. In my studies of populations in Shropshire (Duffell 2009) I found that, unlike the garden escapes, the native populations were clearly reproducing sexually, often forming large colonies (thousands of plants), only rarely as single plants.
We need to review records of A. napellus sens. lat. to see if it is possible to separate the two taxa and produce more helpful maps. It would also be useful to know where A. napellus ssp. napellus is native and where it is only present as a garden escape. Studies into its ecology might also be valuable in determining it conservation importance. Are native populations entirely restricted to W6, for instance? Anyone recording Monk’s-hood in future should collect sufficient material for confirmation, or at least take good-quality photographs of the flowers. I would be happy to look at specimens or photos: email duffell@bsbi.org.uk.
- Brayshay, B.A. and Dinnin, M. 1999. Integrated palaeoecological evidence for biodiversity at the floodplain-forest margin. Journal of Biogeography 26, 115-131.
- Duffell, M.S. 2009. The distribution and native status of Monkshood, Aconitum napellus L., in Shropshire. Msc dissertation, School of Biosciences, University of Birmingham.
Tags: Woodland