Azolla pinnata

Common Name: feathered mosquitofern

Family: Azollaceae

Common Synonyms: Azolla imbricata

USDA Hardiness Zone: 11

Growth Habit: Free-floating aquatic fern

Origin: Asia

FISC Category: -

FDACS Listed Noxious Weed: No

Introduction Date: Earliest Florida specimen vouchered in 2008

IFAS Assessment:

• North: PROHIBITED
• Central: PROHIBITED
• South: PROHIBITED

Description

Leaves minute, 1 -2 mm long, overlapping in 2 ranks, upper lobe green, brown green or reddish, lower lobe translucent brown. The leaves often have a maroon-red tinge and the water can appear to be covered by red velvet from a distance. The upper surface of the leaves are totally water-repellant, and if completely submerged the plants quickly refloat with the right side up. Overall, roughly triangular in shape, the basal branches becoming pinnate. Roots with fine lateral rootlets.

Habitat

Freshwater ponds and swamps

Comments

It has the ability to survive on moist soil in and around rivers, ditches, and ponds which may allow the plant to survive low water levels and periods of drought. (NC Aquatic Fact Sheet) Azolla filiculoides, a native species, is very similar in general appearance, but has a less strongly triangular shape overall.

Control Methods

• Manual: NA
• Chemical: NA
• Biological: There was some success in management of A. pinnata using weevils in South Africa although the study was aimed primarily at Azolla filiculoides.

Control Notes

NA

References

Dave's Garden. 2014. PlantFiles: Ferny Azolla, Azolla pinnata. http://davesgarden.com/guides/pf/go/1850/. Accessed on June 20, 2014.

Wunderlin, R. P., and B. F. Hansen. 2008. Atlas of Florida Vascular Plants (http://florida.plantatlas.usf.edu/).[S. M. Landry and K. N. Campbell (application development), Florida Center for Community Design and Research.] Institute for Systematic Botany, University of South Florida, Tampa.