Salvinia is a floating, rootless aquatic fern. It consists of horizontal stems that float just below the water surface that produce a pair of floating or emergent leaves. Floating and emergent leaves are green. Plants bear a third leaf that is brown, highly divided and dangles underwater. Submersed leaves are commonly mistaken as roots. They may grow to great lengths, and by creating drag, act to stabilize the plant. Salvinia is a very aggressive plant that can rapidly cover the surface of a water body.