Some plants that grow in rivers are cattails, yellow water lilies, floating duckweed and water hyacinth. Other plants found in rivers are water cress and fontinalis, or fountain moss.
Cattails are found along the banks of rivers. They are notable for their long, blade-like leaves and flowers, which have two parts. The more conspicuous brown cylinders contain the female flowers, while the less noticeable yellow spikes contain the male flowers. Cattails can grow as high as 10 feet.
The yellow pond lily, or spatterdock, is found in slow-moving rivers. It is a perennial that is related to the water lily and produces large green leaves that either float on the water or are held above it. The plant also produces a yellow flower.
Duckweed is a free-floating plant with tiny green leaves that is also found in slow-moving rivers. Occasionally, the plant sprouts three minuscule flowers. Duckweed provides cover for tadpoles, fish fry and insect larvae.
Water hyacinth is known for its spectacular, orchid-like flowers, but it is also known for being invasive. It grows so quickly that it can cover small lakes and ponds in a short amount of time, it is also problematic for river traffic, since the plant floats freely and reproduces via stolons.