More than 600,000 plant species have been deleted from the dictionary of life after the most comprehensive assessment carried out by scientists.
For centuries, botanists from different parts of the world have been collecting and naming "new" plants without realising that many were in fact the same. The humble tomato boasts 790 different names, for example, while there are 600 different monikers for the oak tree and its varieties.
The result was a list of more than 1 million flowering plant species. Although experts have long known that it included many duplicates, no one was sure how many. Later this year, the study team, led by UK and US scientists, will announce that the real number of flowering plant species around the world is closer to 400,000.
The project - which has taken nearly three years - was the number one request made by the 193 government members of the Convention on Biological Diversity at their meeting in 2002. There were concerns that without this work, it would be impossible to work out how many plants were under threat and how successful conservationists were in saving them.
The information will also be vital for any organisation or researcher looking at "economically important" plants, such as those for food and nutrition or medicine, said Alan Paton, assistant keeper of the herbarium at the Royal Botanic Gardens at Kew, west London, one of the four leading partners in the project.