Twice as many plants have been driven to extinction over the past 250 years as all the birds, mammals and amphibians combined, a 30-year project has found.
Scientists, including experts from The Royal Botanic Gardens at Kew, discovered that 571 species had disappeared in the wild since the 18th century.
Rafael Govaerts, a Kew botanist, spent 30 years reviewing publications on plant extinctions and found the number was four times more than currently registered, with species disappearing at 500 times the natural rate. Many have been eradicated through man-made habitat loss - such as the Hieracium hethlandiae, a flower wiped out through overgrazing by sheep on Shetland.
Mr Govaerts said: "It's very bad. We're already past a runaway point. Every species that becomes extinct is supporting other organisms that also become extinct at the same time, and many we don't even know about before it happens." The study found the highest rates of extinction to be on islands, in the tropics and in areas with a Mediterranean climate.