An annual of dry, calcareous, open grassland and railway banks. Seed is freely produced but is poorly dispersed, with colonies appearing in the same place year after year. Lowland.
C. brachypetalum was first discovered in Britain in Bedfordshire in 1947; its late discovery and proximity to railways suggest that it is an introduction. However, Palmer (1994) argued that its occurrence in old, Bromopsis erecta dominated grassland on chalk in W. Kent indicates that these populations are relics of a more widespread distribution in this area.
A European Southern-temperate species.
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Light (Ellenberg): 9
Moisture (Ellenberg): 3
Reaction (Ellenberg): 8
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 3.4
July Mean Temperature (Celsius): 16.3
Annual Precipitation (mm): 657
Height (cm): 30
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 2
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
RDB Species Accounts
Cerastium brachypetalum Pers. (Caryophyllaceae)
Status in Britain: ENDANGERED.
Status in Europe: Not threatened.
C. brachypetalum is a late-comer to the British flora, having been first discovered in 1947 in a railway cutting at Wymington in Bedfordshire. When first seen there, it was described as being "in large quantity over a considerable distance". Plants were mostly found on anthills in Brachypodium pinnatum-dominated grassland. The population, mainly in two colonies on west-facing banks, remained fairly constant for years, but in the 1980s a decline set in, and only small numbers have been seen in recent years, fewer than twenty plants in 1993 (Horn 1994). In 1973, the colony was found to extend just into Northamptonshire, but no plants have occurred in that county since 1990. A single plant was detected in 1984 in Wymington Fields Nature Reserve, which lies close to the railway.
The other area where C. brachypetalum is known is in West Kent. Its discovery there was of particular interest since it not only occurs on railway embankments, but in old grassland on chalk nearby. It has been known from about eight locations near Longfield over a distance of about 1 km, mostly in the more open habitats associated with old grassland, such as the edges of paths or on eroding earth banks. The species also occurs in former old grassland sites now altered by disturbance. In most sites, Bromopsis erecta is generally the dominant grassland species, but a wide range of associated species include those characteristic of chalk grassland together with common early-flowerers of ruderal habitats such as Arabidopsis thaliana, Cerastium glomeratum and Erophila verna. A survey of all six of the extant Kent sites in 1994 revealed a total of about 2,500 plants (Rich & Palmer 1994).
C. brachypetalum is a winter annual, varying in abundance from year to year, probably depending on prevailing weather conditions. Seed has been shown to remain viable in storage for at least three years (Brett 1955), and germinates rapidly after cold treatment, but viability in natural conditions is not known. Flowering is in April and May (perhaps into June in a cool wet spring), and flowers are probably self-pollinated. Fruit is set from May onwards. Palmer (1994) has observed that many colonies appear in exactly the same areas each year (to within a few centimetres), thus suggesting very poor powers of dispersal.
The status of C. brachypetalum is uncertain, not least because of its occurrence in both areas near railways. However, its presence in semi-natural grassland in Kent has led some to suppose it might be a relic native species, more abundant in the past, but now able to survive only in the tiny areas which have escaped the plough and development. Conversely, it could have colonised this grassland from railway banks. The proposals for line widening for the Channel Tunnel Link pose a serious threat to the species and, if implemented, would result in the loss of five of its six extant sites and 85% of the British population. However, options for conserving C. brachypetalum in the face of such development are under discussion. In Bedfordshire, some controlled burning in 1994 and 1995 to open up the sward seems to have been beneficial, and more than 60 plants were counted there in 1995.
This species occurs right up to the Channel coast of France, and is widespread throughout western and central Europe. It also extends eastwards to Bulgaria and the Crimea, and northwards to southern Sweden and Norway.
M. J. Wigginton