Worcestershire Record No. 6 April 1999 p. 15
Although widespread and locally abundant in parts of Europe and Western Asia, Thlaspi perfoliatum the Cotswold Pennycress is believed to have always been rare in Britain where it is at the northern limit of its European distribution. It is now a seriously declining plant nationally, surveys between 1986 and 1997 suggesting a catastrophic loss of 80% of native and 92% of introduced colonies. Consequently, it is a Red Data Book species which in 1992 was afforded protection under Schedule 8 of the Wildlife and Countryside Act 1981. Plantlife too are taking steps to conserve the plant by including it with about 20 others in its "Back from the brink" project.
First recorded in England in 1689 from Oxfordshire, the present population is largely restricted to about a dozen sites in that county and also Gloucestershire, and until recently has never been reliably recorded in Worcestershire (although there is a 19th century record of a single casual plant from Evenlode, formerly part of ancient administrative Worcestershire but biologically part of VC33 - East Gloucestershire). Thlaspi perfoliatum is largely restricted as a native to screes and open grassland on shallow soil on an oolitic limestone base rock. As an introduced plant, it also grows in various artificial habitats including railways, quarries and arable fields, and it was in the margin of a calcareous arable field that in April Keith Barnett, one of the Worcestershire Flora Project's recorders, came across a huge colony near the Gloucestershire border in VC37.
After initial determination by the finder, Bill Thompson and Roger Maskew, the plant was vouched by Dr Tim Rich of the Department of Biodiversity at the National Museum of Wales. The Worcestershire Wildlife Trust was immediately informed, so that the owner of the field could be identified and consideration given to the future protection of the colony by maintaining the open conditions required for its survival. On 4th May, the site was visited by Dr Rich and Belinda Wheeler of Plantlife, accompanied by Messrs Barnett, Thompson and Maskew. A count revealed that there were probably in the region of 5,000 plants, which makes this the third or fourth largest site in Britain. Moreover, Dr Rich's assessment of the geological and other conditions of the site lead him to believe that even though in an arable margin, the colony is nonetheless probably native and of long-standing. He has no doubt that the discovery is of national importance.
The Worcestershire Flora Project is extremely grateful to both Dr Rich and Belinda Wheeler, and in respect of background material above acknowledges with thanks Dr Rich's article in Biodiversity and Conservation 7 (1998).
|RICH TCG 1991 Crucifers of Great Britain and Ireland. BSBI Handbook No 6. BSBI London|
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