Ferns and Fern Allies in the Canberra Region
Azolla pinnata - Ferny Azolla
pinnata is a member of a genus of six species of free floating aquatic ferns,
and is one of two recorded in the Canberra Region. It grows in dense patches among
the reeds along Lake Burley Griffin, among other places. The image to the right
shows it growing in a typical location among the reeds. This year there have been
large patches of it easily visible from a distance. The individual plants are
very small, less that 2.5 cm (1") across. They clump together to blanket
open water where they are protected from water movement or wind.
image to the left shows the patchwork of individual plants. The "fronds"
are either a pale green or with reddish patches. In some places the entire plant
can be reddish. This is most likely an environmental response, as it seems to
occur in places where there is direct sunlight and/or foetid water. A. pinnata
differs from a similar species that grows in this region, A. filiculoides,
by having lateral-branching roots that dangle in the water below the leaf. It
also has fuller, more "fern-like" leaflets.
This image is a close-up of an individual plant, showing the red and green coloration.
The fern occurs in all mainland
Australian states. It grows easily in aquarium tanks, especially if encouraged
by a little fertilizer.