Learning to float: Evolution of floating-leaved habit in the aquatic plant genus Nymphoides (Menyanthaceae)

Aquatic vascular plants occupy a specialized niche in nature, where they take advantage of abundant water and relatively low competition. Evolving to utilize the aquatic habitat, however, requires adaptations that allow the plants to cope with water-related challenges like obtaining atmospheric gases and maintaining flower function. Nymphoides are a group of plants with floating leaves that support insect-pollinated flowers, whose nearest relatives are emergent wetland plants. Comparison of molecular (DNA) phylogenetic relationships with the morphology of Nymphoides species allowed us to reconstruct the mechanism by which the emergent ancestor of the genus evolved floating leaves and thus was able to colonize open-water habitats.