Scientific Name: Azolla mexicana
Other/Previous Names: Mexican Mosquito Fern
Taxonomy Group: Vascular Plants
Range: British Columbia
Last COSEWIC Assessment: November 2008
Last COSEWIC Designation: Threatened
SARA Status: Schedule 1, Threatened
Image of Mexican Mosquito-fern
Mexican Mosquito-fern Azolla mexicana is a tiny floating aquatic fern found in wetlands and small wet areas. Individual plants range in size from 1-2 cm in length. Leaves are tiny and overlap like shingles. Spore-producing structures, borne below the water surface, are present in the Canadian populations. Roots are simple and short. Plants usually have three “floats”. This species forms extensive green or red mats on the water surface. (Updated 2017/01/20)
Distribution and Population
The natural range of Mexican Mosquito-fern is North, Central and South America (from Peru, northern Bolivia and Brazil north). In Canada, it is restricted in occurrence to British Columbia, where it occurs at the northern tip of its range. The eight extant British Columbia populations occur in three regions: the Little Fort area, the Shuswap Lake area, and Vernon. The extent of occurrence is 5400 km2 and the area of occupancy for the small fragmented water bodies is 11 km2 based on a 1 x 1 km grid and 40 km2 based on a 2 x 2 km grid. (Updated 2017/01/20)
Mexican Mosquito-fern is a wetland species of sheltered still waters and is found in ponds, ditches, oxbow ponds, and lakeshores. It grows best in 50% sunlight, and is tolerant of semi-shade conditions. In BC, it is found in sites with pH ranging from 6.5- 8.1, although it is tolerant of pH ranging from 3.5 to 10. (Updated 2017/01/20)
This aquatic fern grows in a symbiotic relationship with a species of bluegreen alga (a cyanobacterium) Anabaena azollae. Primary reproduction is through fragmentation of plants. Secondary reproduction is sexual through spore production. This is a heterosporous fern: two types of spores (of different sizes and appearance) are produced that fall to the bottom of water bodies and eventually germinate, producing new plants. Dispersal is by wind, waterfowl, and accidentally by humans. (Updated 2017/01/20)
Mexican Mosquito-fern is naturally limited by factors such as water chemistry and temperature, which restrict its range in British Columbia. Threats to the populations include road repairs and construction, housing / urban development, accidental spills on roads and railways (which can influence water chemistry and could cause complete population die-off), invasive species, and eutrophication of sites. (Updated 2017/01/20)
Federal ProtectionThe Mexican Mosquito-fern is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
Provincial and Territorial Protection
Status of Recovery Planning
Recovery Strategies :
Name Recovery Strategy for the Mexican Mosquito-fern (Azolla mexicana) in Canada
Status First posting on SAR registry
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
6 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Recovery Strategies (1 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
- Recovery Document Posting Plans (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2009 (2009)2009 Annual Report to the The Minister of the Environment and the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
Recovery Document Posting Plans
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