Duckweeds are a treat for many aquatic animals like ducks and snails, but for pond owners, they’re sometimes a thorn in the side. The tiny and fast-growing plants are of great interest to researchers, not at least because of their industrial applications—for example, to purify wastewater or generate energy. An international research team from Münster, Jena (both Germany), Zurich (Switzerland) and Kerala (India) have recently studied the genomics of the giant duckweed. They discovered that genetic diversity, i.e. the total number of genetic characteristics that are different among individuals, is very low. “This is remarkable given that their population size is very large—there can, for example, be millions of individuals in a single pond,” says Shuqing Xu, professor for plant evolutionary ecology at the University of Münster and lead author of the study.