One in five plants are estimated to be threatened with extinction from habitat loss, disease and invasive species, according to a report by the Royal Botanic Gardens, Kew.
In total, 391,000 types of plants are known to science, from tiny orchids to giant sequoia trees and 2,000 new species of plant are discovered every year.
"This is the first ever global assessment on the state of the world’s plants," said Professor Kathy Willis, Director of Science at the Royal Botanic Gardens, Kew.
"We already have a ‘State of the World’s birds, sea-turtles, forests, cities, mothers, fathers, children even antibiotics’ but not plants.
"I find this remarkable given the importance of plants to all of our lives– from food, medicines, clothing, building materials and biofuels, to climate regulation.
"This report therefore provides the first step in filling this critical knowledge gap."
The biggest threats to plant species are destruction of habitats, deforestation for timber and construction of new buildings.
More than 391,000 species of vascular plants, a large group of plants which conduct water and minerals, have been registered around the world.
Some 17,810 plant species have a medical use, 5,538 are food and 3,649 are animal feed, the report said.
