One in five of the world's 380,000 plant species is threatened with extinction and human activity is doing most of the damage, according to a global study.
Scientists from Britain's Botanic Gardens at Kew, London's Natural History Museum and the International Union for the Conservation of Nature (IUCN), found that more than 22 per cent of species were endangered, critically endangered or vulnerable.
"The picture that comes out of the survey is rather bleak, I'm afraid. One in five of our plants is threatened with extinction," said Eimear Nic Lughadha, Head of Science Policy and Co-Ordination at the Millennium Seed Bank in West Sussex, England.
As this was the first time a global analysis of the threat to the world's plants had been undertaken, the scientists said it would serve as a baseline to measure conservation efforts.
Both common and rare plants species were assessed to try to give an accurate picture of how plants were faring around the world.
Researchers studied a random sample of about 1,500 species from each group, since assessing the threat to all the world's estimated 380,000 plant species would be too enormous a task, they said.
The findings were released ahead of a United Nations summit scheduled for mid-October in Nagoya, Japan where governments are due to set new targets for trying to conserve more of the world's plants and animals.