Aeschynomene fluitans

Native to tropical Africa from Congo to Tanzania and Namibia, this aquatic perennial herb floats on the surface of permanent swamps. Its hollow, spongy stems can extend about 3 to 15 feet and produce numerous roots along their length. The feather-like leaves consist of many paired leaflets. Yellow pea-shaped flowers arise singly beside the leaves, followed by flattened, jointed pods that are constricted between their seed-bearing segments. Nitrogen-fixing bacteria form nodules on its floating stems as well as its roots. Photographed in Florida.