An audit of more than half a million museum specimens collected from the Amazon rainforest since 1707 has revealed its startling diversity.
So many different tree species grow in the Amazon rainforest that it will take another 300 years to discover them all, say scientists.
Researchers made the prediction after conducting an audit of more than half a million museum specimens collected from the Amazon between 1707 and 2015.
They ended up with a list of 11,676 different tree species. Based on this figure, they believe about 4000 of the rarest Amazonian trees remain to be discovered and described.
Conservationist Dr Nigel Pitman, from the Field Museum in Chicago, US, said: "Since 1900, between 50 and 200 new trees have been discovered in the Amazon every year.
"Our analysis suggests that we won't be done discovering new tree species there for three more centuries."
In 2013 scientists guessed there were around 16,000 tree species in the Amazon.
The new study, published in the journal Scientific Reports, suggests this estimate is probably a good approximation.
It was made possible by the digitisation of museum collection data - photos and records of specimens that can be shared online by experts around the world.
"We couldn't have written this paper without digitisation efforts," said Dr Pitman. "All of the information we needed was in the same place, so we didn't have to go through every individual museum in the world. We were able to use data not just from the Field Museum, but from museum collections everywhere."
The species list will assist those trying to preserve the rainforest in the future, said the scientists.
Co-author Dr Hans ter Steege, from the Naturalis Biodiversity Centre in Leiden, the Netherlands, said: "We're trying to give people tools so they're not just labouring in the dark. The checklist gives scientists a better sense of what's actually growing in the Amazon basin, and that helps conservation efforts."