Crepis praemorsa
Ecology
A perennial herb, confined to low banks of limestone drift at the edges of a hay meadow and grazed pasture, at an altitude of 240 m (Westmorland).
Status
Trends
This species was found for the first time in Britain (and W. Europe) in Westmorland in 1988. In 1996, the population comprised about two hundred individuals. Doubt has been expressed about its status, and it is regarded as an archaeophyte in some European countries. However, the similarity of its British and Scandinavian habitats and the undisturbed nature of the site suggest that it may be native in Britain.
World Distribution
Eurosiberian Temperate element, with a continental distribution in W. Europe.
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Broad Habitats
Light (Ellenberg): 8
Moisture (Ellenberg): 3
Reaction (Ellenberg): 9
Nitrogen (Ellenberg): 3
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 1.7
July Mean Temperature (Celsius): 13.3
Annual Precipitation (mm): 1333
Height (cm): 60
Perennation - primary
Life Form - primary
Woodiness
Clonality - primary
Count of 10km squares in Great Britain: 1
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Plantatt Conservation Status
JNCC Designations
RDB Species Accounts
Crepis praemorsa (L.) Tausch (Asteraceae)
Leafless hawk's-beard
Status in Britain: ENDANGERED.
Status in Europe: Not threatened.
The discovery of C. praemorsa in northern Westmorland in 1988 makes this species one of the most recent additions to the British flora (Halliday 1990). It occurs on the banks of a stream, on both sides of a boundary wall which crosses it and separates a hayfield from grazed pasture, the whole population occurring along a stretch of about 150 metres. Most plants occur on the sloping banks of limestone drift about a metre above the stream level, in short rather open turf. The wide range of associates on the hayfield side of the wall includes Briza media, Campanula rotundifolia, Carex ornithopoda, C. panicea, Danthonia decumbens, Festuca ovina, Gentianella amarella, Koeleria macrantha, Leontodon hispidus, Lotus corniculatus, Pimpinella saxifraga, Scabiosa columbaria, Serratula tinctoria, Stachys officinalis, Succisa pratensis and Thymus polytrichus. A few plants occur at the top of the stream bank at the edge of rank vegetation in which such species as Centaurea nigra, Festuca rubra and Sanguisorba officinalis are prominent. Plants of C. praemorsa in the closely-grazed pasture are more scattered, smaller and generally with fewer leaves than those on the ungrazed banks adjoining the hayfield. It generally has fewer associates in the grazed area, but they include some of those species listed above.
C. praemorsa is a perennial, and is distinct from other Crepis species in Britain in its leafless flowering stems, and rosette of narrowly-obovate leaves which are shallowly-toothed in the basal part. Flowering is from late May into June. Few plants produce flowering stems, and there appears to be no seed-set, even in cultivation, suggesting that the population may be a single self-sterile clone. In cultivation, plants produce new rosettes freely alongside the old ones. It also rapidly forms a large root system, with new rosettes arising where it is damaged. This suggests that the plant can colonise effectively by vegetative means, and it seems likely that the wild population has spread along the stream banks by these means over a long period.
C. praemorsa is currently known from only one site in Britain, the whole population occurring within an SSSI. In June 1989, ten flowering plants and 150 non-flowering rosettes were seen (Halliday 1990). In August 1996, plants were difficult to find in the taller herbage at that time of year (F.J.Roberts & M.S.Porter). However, its presence was confirmed in all but one of the areas recorded in 1989, and rosettes were also found in new areas. It has been recorded in eleven discrete small colonies of 5-35 rosettes, and an additional larger one of about 70 plants, with a total population of about 200 individuals.
Because of its occurrence in undisturbed semi-natural grassland, it seems likely that this species is native to Britain, though some authorities (e.g. Stace 1991) have cast doubt on its native status. Searches of banks and hay meadows in other traditionally farmed areas may reveal its presence elsewhere.
It has a wide range in Europe and Asia, from eastern France, Denmark and south-east Norway, eastwards through Asia to northern China. The Westmorland site represents a considerable extension of its known range.
F. J. Roberts, M. S. Porter and M. J. Wigginton