Azolla pinnata

fern

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Last updated

July 22, 2026

Quick Summary

Azolla pinnata is a species of aquatic fern, commonly known as mosquito fern. These small ferns float on the surface of still, fresh water and can sometimes cover the entire water surface, preventing mosquitoes from laying eggs.12

A key characteristic of Azolla is its symbiotic relationship with the cyanobacterium Anabaena azollae. This alga lives within the fern's leaves and converts atmospheric nitrogen into a form usable by plants, effectively acting as a natural fertilizer. This nitrogen-fixing ability makes Azolla highly valuable in agriculture, particularly for rice cultivation in Asia, where it significantly boosts grain yields. The fern also provides habitat for the alga, creating a mutually beneficial partnership.32

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mosquito fern
Agricultural importance
Originally, these were from A. pinnata, the species used in traditional agriculture in Southeast Asia and native to the region. However, in the late 1970s, it was discovered that the American A. filiculoides also yielded good results and was more resistant to various diseases, so strains of this species…
Read More
Originally, these were from A. pinnata, the species used in traditional agriculture in Southeast Asia and native to the region. However, in the late 1970s, it was discovered that the American A. filiculoides also yielded good results and was more resistant to various diseases, so strains of this species…
Read More