Number of known species of giant waterlilies almost doubles

Giant waterlilies are not exactly inconspicuous plants. But in the past few years, we have discovered no fewer than three new species, taking the total to five. The latest species to be described was identified with the help of social media, satellite photos and a mad jungle dash in the dark.

“I think it’s incredible that we find something so new, which is so large, in this world where we think everything is already known,” says Maarten Christenhusz at the Botanical Society of Britain and Ireland, who has helped describe two of the new species.

Giant waterlilies are famed for their massive leaves, which grow up to 3 metres wide. For many decades, just two species were known: Victoria amazonica and Victoria cruziana. Then in 2016, Carlos Magdalena at the Royal Botanic Gardens in Kew, London, noticed that giant waterlilies grown from seeds from Bolivia were a bit different, with even larger leaves. In 2022, Magdalena and his colleagues published a paper showing that this was a new species, Victoria boliviana.

Magdalena hasn’t stopped there. In 2021, Jeremiah Harris, who runs a carnivorous plant business in the US, posted pictures online that he took while swimming near the Inírida river in Colombia next to what he assumed was V. amazonica.

Magdalena was struck by the photos because scientists had thought there were no giant waterlilies in this region. “This river is geographically completely separated from the Amazon, and has been for millions of years, and that is why this is such an interesting find,” says Christenhusz.

Magdalena, Christenhusz and their team examined satellite photos and found telltale green dots confirming there really were giant waterlilies growing there. They then organised an expedition to the region. The team found two plants but neither was flowering – and analysing the flowers is a crucial step in establishing whether a waterlily really is a new species.

At 11pm on the last night of the expedition, with the plane due to leave at 9am, the researchers seemed to have failed. Then one of the guides, Gustavo Melo from the Indigenous Tucano community, said he knew where some more giant waterlilies were growing. The team set off by boat in the dark, and found five plants in a small lake just before sunrise, including some that were flowering.

Magdalena, Christenhusz and their colleagues have now published a paper describing the new species, which they have named Victoria colombiana. It differs from V. amazonica in the orientation of the spines beneath the leaves, and in the shape of its flowers and fruits. The spines are a defence against manatees and plant-eating fish, Christenhusz says, so they vary between species depending on which herbivores are most prevalent.

As far as the team is aware, V. colombiana is found in only one small area. A single event, such as a pollution spill, could wipe out the entire species, says Christenhusz. But the team is planning to try to collect seeds to help ensure the species survives.

Meanwhile, Magdalena also realised that the giant waterlilies growing in the Pantanal region of South America, hundreds of kilometres to the south-east of Colombia, must have been isolated from other populations for a very long time. Sure enough, genetic studies revealed that they are another distinct species, despite looking very similar to V. cruziana. Magdalena, Christenhusz and their colleagues will publish a paper soon to describe this fifth species, which they have decided to name Victoria mattogrossensis.