About Hydrocotyle ranunculoides L.fil.
This species, commonly known as water pennywort or floating pennywort, has horizontally spreading stems that are able to float on water. Its leaves grow on petioles that can reach up to 35 cm in length, and are shaped round to kidney-shaped, with 3–7 lobes and crenate to entire margins. The small flowers range in color from pale greenish white to pale yellow, and grow in umbels that hold 5–13 flowers each. The fruits are small achenes that can float, which aids in seed dispersal. The South American weevil Listronotus elongatus lays its eggs on floating pennywort and eats the plant, while the weevil larvae tunnel into and eat the plant's stems, reducing the pennywort's capacity for growth. After extensive research confirmed the weevil itself does not pose a threat, it has been introduced into British waterways to act as a biocontrol agent for floating pennywort.
