Other names: Red Azolla.
Family: Azollaceae (Azolla family).
Native of Australia and elsewhere.
Occurrence: Pacific Azolla is a free-floating fern that grows on dams, and on stagnant or slow-moving water. It may form a dense carpet over the water surface.
Identification:
- it floats on the water
- the fronds (leaves) are branched and are several centimetres across
- the fronds are deeply lobed and are green to reddish.
Notes: The upper lobes of the fern contain nitrogen-fixing algae. In some countries, the fern is harvested and used as a fertilizer. The fern may block water pumps and deter stock from drinking.
Similar plants: Ferny Azolla has more regular fronds. See the photo below. It has a doubtfull occurrence locally.
Photos:
1: Pacific Azolla, showing the branches and divided leaves. The roots are dangling in the water.
2: Pacific Azolla. Melbourne Museum. 3: Pacific Azolla carpeting the surface of Cambells Creek. Yapeen.
4: Milfoil is growing among the fern. The taller Common Reed is also present. Malmsbury Botanic Gardens. 5: Ferny Azolla (Azolla pinnata)is much less common than Pacific Azolla. Newcastle.