ONE plant species disappears from the County Durham countryside every 15 months - one of the highest rates in the country - a survey has revealed.

Plantlife's review of the county-by-county decline and loss of Britain's wild flowers revealed the statistic.

In County Durham, 68 species of vascular plants were lost between 1900 and 1988, an extinction rate of 0.8 per year, one of the highest rates in the country.

Those which have been lost include Corncockle, alpine foxtail, nodding bur-marigold and field gromwell.

Vascular plants have leaves, stems and roots, and include all the flowering plants, three native conifers and ferns and horsetails.

The conclusions were found by leading botanist Peter Marren, who analysed plants in 14 counties to discover the status of England's wild flowers.

The statistics show that many native species declined steadily throughout the 20th Century, though most species in decline are not necessarily nationally endangered.

Rural counties have experienced declines similar to predominantly urban ones.

The review suggests that this is because farm chemicals are as damaging to the landscape as bricks and mortar. Rising soil nutrient levels and falling water tables in the latter half of the last century also had a disastrous effect on wild plant populations.

Martin Harper, Plantlife's conservation director, said: "The loss of so many species at a local level last century is appalling. There is no evidence that the rate of decline is slowing down.

"In fact, based on current trends, it looks as though we might lose one species from each county this year.

"Certainly, more local extinctions will follow, and sooner or later another species will become nationally extinct.

"Vigorous, aggressive plants which flourish in fertile soils are taking over our countryside, swamping the majority of wildflowers that thrive best in naturally infertile conditions.

"Is this the countryside we want for our grandchildren?"

Plantlife, a conservation charity, acts to prevent the loss and decline of wildflowers and urges everyone to work to reverse these declines by preventing habitat destruction and neglect, stopping pollution and changing harmful agricultural practices.

More information is available from the Plantlife website on www.plantlife.org.uk, or write to Plantlife, 21 Elizabeth Street, London, SW1W 9RP.