Feathered Mosquitofern

Feathered Mosquitofern

Feathered mosquitofern (Azolla pinnata) is a free-floating small aquatic fern that is distinguished from the native Azolla filiculoides by its triangular Christmas tree shape. It is found in small still ponds and can survive in moist soil during the drier seasons. This species spreads rapidly and can form dense mats which can cover entire water bodies blocking sunlight to the environment below. Azolla pinnata is on the Federal Noxious Weed List and is prohibited in Florida. This species is part of the Early Detection Rapid Response program. If you see this plant in the wild, please report it immediately.

Common Name: Feathered Mosquitofern

Species Name: Azolla pinnata

Growth Habit: Small free-floating aquatic fern

Origin: Africa, India, Southeast Asia, China, Japan, Malaysia, the Philippines, New Guinea, Australia

Counties Confirmed: Martin, Palm Beach, Leon, Miami-Dade

Description: Very small leaves that can be bright green at the top of the plant and brown-green or reddish towards the bottom of the plant. The entire plant is between 0.5-1 inch long, growing very close together forming large mats. From a distance, the water can appear to be covered in reddish velvet. The rootlets grow up to 2 inches long with feathery-looking root hairs. The plant has an overall triangular shape.

Habitat: Very still ponds, lakes, and swamps protected from wave action.

Comments: This species can survive out of the water on moist soils when water levels drop. It can be distinguished from the native Azolla filiculoides by its distinctive Christmas tree shape.

Map indicating the three counties Feathered mosquito fern has been vouchered in.

Look for:

Bright green leaves on the pointed end of the plant and red-brown leaves towards the wider base.

A large mat covering a waterbody can make the water appear to be covered in red.

Waterbody covered in a large mat of red appearing feathered mosquitofern.

Distinctive triangle shape.

Close up view of the small leaves of the mosquitofern.

Feathered mosquitofern is able to float into inaccessible spaces along the banks and survive in moist soil when water levels drop.

Feathered mosquitofern floating on water.

What can you do to help protect Florida waters?

Report all feathered mosquitofern sightings! Call the FWC Invasive Plant Management office at 1-850-617-9430

Do not plant or transport feathered mosquitofern. It is prohibited in the United States by Federal law.

Clean, drain, and dry all gear completely before entering another water body. It is easier and much cheaper to prevent an invasive plant from entering a waterbody than it is to manage after it becomes established.

Report Immediately

Please report all plant Early Detection Rapid Response sightings immediately to the FWC Invasive Plant Management office at 1-850-617-9430

Photo credits: University of Florida, David Nicholls