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Kew Scientist discovers new species of aquatic herb on the edge of extinction

In a recently published paper, Kew scientist Dr Martin Cheek and African collaborator Dr Aiah Lebbie, describe the discovery of a bizarre new waterfall genus of Podostemaceae

The new species, Lebbiea grandiflora, which is remarkably distinct in structure compared to other members of the flowering plant family Podostemaceae, was initially identified from a single small and declining population in the Sewa Rapids in Sierra Leone in 2017. However, in 2018 a larger new population was discovered at the Koukoutamba falls in Guinea, as part of a survey of priority habitats for Kew’s Guinea Tropical Important Plant Areas project. It is the first new African genus of Podostemaceae published for 30 years.

There are approximately 300 species of Podostemaceae and they grow exclusively on bare rocks in waterfalls and rapids, thriving only in clear, aerated freshwater. While some species are only two millimetres tall, others grow to more than 1.5 m in length. Several species are edible while others have medicinal uses and all are so strange that for more than two hundred years, scientists failed to place the family among the other flowering plant families of the world. 

According to the IUCN 2012 standard, the newly described species is assessed as Critically Endangered. A planned hydro-electric dam along with sediment from gold and diamond mining threaten the species with extinction at the single location in the Sewa Rapids. At the new site in Koukoutamba, Guinea the World Bank is reportedly also backing another hydro-electric dam.

Image: The Koukoutamba falls in Guinea on the Bafing River of Guinea-Conakry. With 5 species of Podostemaceae, three globally threatened including two new to science (one of which is Lebbiea), it is the richest site known for Podostem species diversity in Guinea. 

The paper was published 5 October in PLoS One: Cheek, M. & Lebbie, A. (2018). Lebbiea (Podostemaceae-Podostemoideae), a new, nearly extinct genus with foliose tepals, in Sierra Leone. PLoS ONE 13(10): e0203603.