Hydrocharis morsus-ranae, commonly known as European Frog-bit, is a free-floating aquatic plant native to Europe and parts of Asia. It is a member of the Hydrocharitaceae family, which includes other aquatic plants like Elodea. European Frog-bit plays a role in its native aquatic ecosystems, providing habitat and food for various invertebrates and small fish. This perennial aquatic herb is characterized by its floating rosettes of leaves. The leaves are typically kidney-shaped to broadly ovate, measuring about 2 to 5 centimeters in length and width, with a distinctively notched apex that gives rise to its common name, as the notch resembles a frog's bite. The leaf surface is smooth and green, often with a slightly purplish underside. The plant reproduces both vegetatively through runners and by producing small, inconspicuous flowers. Male and female flowers are borne on separate plants, a characteristic known as dioecy. The flowers, which appear in summer, are typically white with three petals, though they are relatively small and often partially submerged. Fruits are small, ovoid capsules containing numerous tiny seeds. In autumn, specialized overwintering buds, called turions, are formed, which sink to the bottom and allow the plant to survive cold periods. European Frog-bit thrives in still or slow-moving freshwater habitats such as ponds, lakes, canals, and ditches. It prefers shallow water with a substrate of mud or silt, where it can anchor its roots loosely. While it is a native species in its range, it has been introduced to other parts of the world, where it can sometimes become invasive due to its rapid growth and prolific reproduction. Cultivation requirements in suitable environments involve providing a stable, nutrient-rich substrate and ample sunlight. Ecologically, European Frog-bit contributes to the biodiversity of aquatic environments. Its floating leaves offer shade and shelter for aquatic organisms, and its presence can indicate healthy, relatively undisturbed water bodies. While not widely cultivated for ornamental purposes, its attractive foliage and delicate flowers can be appreciated in naturalistic water gardens. There is no significant documented use of this species in agriculture, medicine, or culinary practices. An interesting adaptation of Hydrocharis morsus-ranae is its ability to form dense mats on the water surface, which can significantly alter light penetration and oxygen levels in the water column. This can impact the growth of submerged aquatic vegetation and the overall aquatic ecosystem. The formation of turions is a crucial survival strategy, enabling the plant to persist through harsh winter conditions and re-establish itself in the spring.