Marsilea quadrifolia
Common Name : European waterclover Family: Marsileceae Habit: A small aquatic fern. Stem: Slender, creeping rhizome. Leaves: Quadrifoliate with long slender petioles; leaflets obovate-retuse, glabrous, arranged in a whorl. Flowers: Absent. Fruits: Fructifications (Sporocarps) are dark brown, hard, bean shaped, with two unequal horns.