Other forms of algae, including stringy filamentous types, are common only in the littoral area. Submerged plants have stems and leaves that grow entirely underwater, although some may also have floating leaves . Flowers and seeds on short stems that extend above the water may also be present. Depending on the species, they may form a low-growing meadow near the lake bottom, grow with lots of open space between plant stems, or form dense stands or surface mats. Floating-leaf plants are often rooted in the lake bottom, but their leaves and flowers float on the water surface .
Water lilies are a well-known example.
Floating leaf plants typically grow in protected areas where there is little wave action. Emergent plants are rooted in the lake bottom, but their leaves and stems extend out of the water. Cattails, bulrushes, and other emergent plants typically grow in wetlands and along the shore, where the water is less than 4 feet deep. As Figure 1 illustrates, each of the four types of aquatic plants favors a certain water depth. Typically, however, the growth areas are not sharply divided.