International researchers on Wednesday announced the completion of a 1.25-million-entry plant list, which is so far the most comprehensive list of the world's land plant species.

The Plant List was jointly compiled by the Royal Botanic Gardens, Kew in the Britain and the Missouri Botanical Garden in the United States. They merged their own lists of plant names and added data from partners all around the world to produce the list.

"The Plant List is a significant accomplishment for Kew and the Missouri Botanical Garden, and our partners worldwide," said Stephen Hopper, director of Royal Botanic Gardens, Kew. "This is crucial to planning, implementing and monitoring plant conservation programs around the world."

It could help to avoid misunderstanding when talking about plants, because there are so many synonyms for some plant species. Of all the 1.25 million names, 1.04 million are names of species rank, of which 29 percent are accepted names for species and 46 percent are recorded as synonyms of those plant species.

"All validly published names for plants to the level of species have been included in The Plant List, the majority of them synonyms; no names have been deleted," said Peter Raven, president Emeritus of Missouri botanical Garden.

There are some names "unresolved" since the contributing data sets do not contain sufficient evidence to decide whether they should be accepted names or synonyms. And the list will be updated in future as data quality improves.

"It's the most comprehensive list of land plant species based on authoritative sources," said Eimear Nic Lughadha, the Senior Responsible Owner for The Plant List at the Royal Botanic Gardens, Kew.

She also told Xinhua that "it's the largest of its kind," which means synonymized name list for land plants compiled form authoritative resources.

The completion of the list accomplishes Target 1 of the Global Strategy for Plant Conservation, which was first proposed at the International Botanical Congress in 1999. Some of its targets were recognized again in the UN conference of biological diversity in Japan this year.

Its first target called for a widely accessible working list of known plant species as a step towards a complete world flora.