There are many different types of water lilies, which are classified as aquatic herbs. Some are exotic, such as the rare, giant Amazon water lily. Others are commonly seen in ponds around the world, such as the American white water lily, which is considered to be an invasive weed in some states. Regardless of the species, all water lilies have the same basic features.
Water lilies are rooted in the sediment below the surface of fresh water. Although the leaves float, the plant does not actually move. In some species, such as the Nuphar advena, the roots are cooked and eaten as greens.
The stalk of a water lily holds the leaves and flower. This strong, sturdy stem reaches down to the sediment below the water and is topped by the plant's single bloom.
The most easily recognizable features of the water lily are its green leaves. Round, oval or heart-shaped, they float on the water or sit slightly above the water. They are attached at the center to the stalk, and most feature a split that makes them look much like they have an open mouth.
Most varieties (of which there are more than 70) of water lilies have yellow, white or pink flowers. These flowers float on the water or sit slightly above it, much like the leaves. Some tropical species, like the blue water lily, have blue flowers. The Victoria regia of the Amazon features white flowers with a pink center that can be as large as about 16 inches across. The flowers of most water lily plants only last a few days.
The fruit of the water lily varies widely. Some produce nuts. Others produce berries, or a dehiscent capsule. In many varieties, the flower petals close to protect the reproductive parts of the flower. Then the flower submerges, and the fruit develops underwater. Once released, the seeds float until they become waterlogged, when they submerge and root.