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- From: "James Allison" <jallison@aquapic.com>
- To: gwl-g@lists.ibiblio.org
- Subject: [gwl-g] Re: Fairy Moss and Duckweed
- Date: Sat, 29 May 2004 18:55:34 +0100
Duane asked why Azolla (Fairy Moss) does so much better than duckweed
in his pond.
Azolla has a symbiotic relationship with a nitrogen fixing blue green
algae (=cyanobacteria) called Anabaena. The algae is found around the
base of the plant and in cavities within the leaf. This means that
even in water with a low nutrient content, the Azolla can grow using
nitrogen from the air, fixed by the Anabaena.
Azolla has the capability to grow very rapidly, and like duckweed, it
is all too easy to introduce it by accident, as a lurker on other
plants.
Azolla pinnata (Christmas Tree Azolla) is on the Federal Invasive
Plants list in the USA. Azolla filiculoides/caroliniana are found in
many countries.
Here in the UK there is debate as to whether Azolla should be
considered an alien invasive plant, and banned from sale. Azolla
filiculoides is now so widespread that elimination would be virtually
impossible. It has also been found in fossil records, suggesting that
it has re-established in the UK following a period of absence
following the last ice age. Climate change and milder winters are
resulting in a number of such plants becoming more strongly
established.
James Allison
- [gwl-g] Re: Fairy Moss and Duckweed, James Allison, 05/29/2004
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