Campanula patula

Taxonomy 

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).

Campanula patula

Photograph: A.J. Lockton

Distribution 

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.

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Status 
  • 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.
Ecology 

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.

Campanula patula

Photograph: A.J. Lockton

Further Work 

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.

References 
  • 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.
Citation 
Lockton, A.J. (Date accessed). Species account: Campanula patula. Botanical Society of the British Isles, www.bsbi.org.uk.

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