Mosquito fern
Azolla filiculoides · Aquatic plants
A stand of it · Photo: Adam J. Searcy / CC BY
Also called Azolla, Water fern, Pacific mosquito fern, Red water fern
How to identify Mosquito fern
- Tiny branching floating ferns 1/2 to 2 inches across
- Overlapping scalelike leaves in two rows
- Turns red or rust in sun, cold or drought
- Fine hanging roots
Similar plants
Duckweeds have smooth oval fronds without scalelike leaves, and Mexican mosquito fern is smaller with spore structures that differ under a lens.
Growth profile
| Growing season | Grows from spring, can cover ponds by summer, turns red in fall, and survives winter as plants or spores. |
|---|---|
| Starts growing | About 50 F water; fastest from 65 to 80 F |
| Light | Full sun to partial shade |
| Depth | Surface of still water of any depth |
| How it spreads | Breaking fronds and spores |
| Habitat | Still, nutrient rich ponds, sloughs and ditches at low elevations. |
Why it matters in a lake
Can form a thick red carpet that shades the water and lowers oxygen. It hosts a blue green bacterium that adds nitrogen to the water.
Where it is found
- Idaho: Rare
- Oregon: Common
- Wyoming: Not recorded
Classification
| Kingdom | Plantae |
|---|---|
| Phylum | Tracheophyta |
| Class | Polypodiopsida |
| Order | Salviniales |
| Family | Salviniaceae |
| Scientific name | Azolla filiculoides |
Common duckweed
Columbia watermeal
Giant duckweed
Star duckweed
Purple fringed riccia
Turion duckweed
Mexican mosquito fern
Least duckweed
Floating crystalwort
Brazilian watermealNeed a hand?
Is it taking over your lake?
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