Azolla pinnata is a small fern with a triangular frond that measures up to 1 in. (2.5 cm) in length and floats on the water.
Foliage
The frond is made up of many rounded or angular overlapping leaves each 0.08 in. (0.2 cm.) long. They are green, blue-green, or dark red in color and coated in tiny hairs, giving them a velvety appearance. The hairs make the top surface of the leaf water-repellent, allowing the plant to float.
Flowers
Ferns do not produce a flower.
Fruit
The small fruit is a capsule that can contain up to 64 small spores.
Ecological Threat
Azolla pinnata can quickly spread to cover open areas of water. It forms dense surface mats that impede water flow and navigation, and clog irrigation pumps. Mats of Azolla pinnata also reduce oxygen levels and the amount of light available to other aquatic organisms. It can be found in lakes, slow moving rivers and streams, ponds and wetlands.