Calflora, a 501c3 non-profit
Distribution by County   10786    
Azolla microphylla  Kaulf.
Mexican mosquito fern
Azolla microphylla is a fern that is native to California, and also found elsewhere in North America and beyond.
also called Azolla mexicana
California Rare Plant Rank: 4.2 (limited distribution).
Record Count by County

Alameda: 4 Madera: 1 Sacramento: 6 Santa Cruz: 15
Butte: 22 Marin: 1 San Bernardino: 7 Solano: 2
Colusa: 1 Merced: 2 San Diego: 1 Sonoma: 10
Contra Costa: 10 Mono: 2 San Francisco: 1 Sutter: 9
Glenn: 5 Monterey: 3 San Joaquin: 4 Tehama: 7
Inyo: 6 Napa: 1 San Luis Obispo: 11 Trinity: 2
Kern: 10 Nevada: 4 San Mateo: 4 Tulare: 2
Lake: 1 Plumas: 8 Santa Clara: 1 Yuba: 2

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2025. The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 12/16/2025).