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Azolla filiculoides
Also called Water fern, Duckweed fern, Large mosquito fern, Pacific Azolla, Fern Azolla, Red Azolla, Pacific Mosquito Fern
Pacific mosquitofern is a fast-spreading floating aquatic fern from the Americas that can cover the surface of still water within months. It is grown in ponds and aquariums and used as a green manure, and it is easy to control by keeping it in water.
Azolla filiculoides (water fern) is a species of aquatic fern. It is native to warm temperate and tropical regions of the Americas, and has been introduced to Europe, North and sub-Saharan Africa, China, Japan, New Zealand, the Caribbean, and Hawaii.
It is a floating aquatic fern with very fast growth, capable of spreading over the surfaces of lakes to give complete coverage of the water in only a few months. Each individual plant is 1–2 cm across, green tinged pink, orange, or red at the edges, branching freely, and breaking into smaller sections as it grows. It is not tolerant of cold temperatures; in temperate regions it largely dies back in winter, surviving by means of submerged buds. It harbors the diazotrophic organism Anabaena azollae in specialized leaf pockets. This ancient symbiosis allows A. azollae to fix nitrogen from the air and contribute to the fern's metabolism.
The species has been introduced to many regions of the Old World, grown for its nitrogen-fixing ability that may be used to enhance the growth rate of crops grown in water, such as rice, or by removal from lakes for use as green manure. A. filiculoides is frequently cultivated in aquariums and ponds, where it can become easily dominant over other species.
Carolina mosquitofern · Mexican mosquitofern · Azolla nilotica · Feathered mosquitofern · Azolla primaeva · Mosquitofern
Text excerpted from the Wikipedia article Azolla filiculoides by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
