feathered mosquito-fern
Azolla pinnata R. Brown


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.
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.
Ferns do not produce a flower.
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.


Selected Images


EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

Taxonomic Rank

Kingdom: Plantae
Phylum: Pteridophyta
Class: Filicopsida
Order: Hydropteridales
Family: Azollaceae
Genus: Azolla
Subject: Azolla pinnata R. Brown

Synonyms and Other Names

Other Common Names:
feathered mosquitofern, feathered mosquitofern, water velvet


Plants - Aquatic Plants