Plants such as artemisia sweet wormwood provide valuable drugs - in this case, for malaria
One-fifth of the world's plants - the foundation of life on Earth - are at risk of extinction, a study concludes.
Researchers have sampled almost 4,000 species, and conclude that 22% should be classified as "threatened" - the same alarming rate as for mammals.
A further 33% of species were too poorly understood to be assessed.
The analysis comes from the Royal Botanic Gardens at Kew, the Natural History Museum and International Union for the Conservation of Nature (IUCN).
There are an estimated 380,000 plant species in all, and many are victims of habitat loss - typically the clearing of forests for agriculture.
Species in tropical rainforests are found to be at greatest risk.
The study, known as the Sampled Red List Index for Plants, is an attempt to provide the most accurate assessment so far. ...
via BBC News - One-fifth of world's plants at risk of extinction.