Common Name: Water Fern

General Information

Water fern is a very small, evergreen plant, only 2.5cm long, floating on water and capable of producing large colonies due to the way it increases by budding off[].
Species of Azolla are of considerable economic importance in countries such as China and Vietnam where they grow in rice paddies and in flooded fields used for other crops such as taro (Calocasia )[]. The symbiotic cyanobacterium Anabaena azollae fixes atmospheric nitrogen, which is made available to the crop as a nutrient when the Azolla dies[]. The plant's rapid vegetative increase is exploited by rice growers as a means of adding bulk matter and humus to the soil[].

Known Hazards

Although we have found no reports of toxicity for this species, a number of ferns contain carcinogens so some caution is advisable[].
Many ferns also contain thiaminase, an enzyme that robs the body of its vitamin B complex. In small quantities this enzyme will do no harm to people eating an adequate diet that is rich in vitamin B, though large quantities can cause severe health problems. The enzyme is destroyed by heat or thorough drying, so cooking the plant will remove the thiaminase[].

Botanical References

,

Range

Widespread in tropical Africa and southeast Asia through to the Pacific including Australia, New Zealand.

Habitat

Ponds and backwaters of rivers at elevations of 3 - 1,000 metres[].

Properties

Weed Potential	Yes
Other Uses Rating
Habit	Evergreen Fern
Height	0.02 m
Growth Rate	Fast
Cultivation Status	Semi-cultivated, Wild

Cultivation Details

Succeeds in tropical and subtropical areas. It grows best in areas where annual daytime temperatures are within the range 20 - 35°c, but can tolerate 15 - 40°c[].
Succeeds in ponds and lakes[]. Plants are able to tolerate a very wide range of pH from 3.5 - 10.5[].
Plants increase so prolifically that they can become invasive[].

Edible Uses

None known

Medicinal

None known

Agroforestry Uses:

The plant is used as a green manure in paddy fields, in particular to add nitrogen and organic matter to the soil[, ].
The nitrogen-rich roots can be added to compost heaps, where they act as an activator to speed up the compost-making process[].

Other Uses

None known

Propagation

Division.

Add a Comment:

If you have any useful information about this plant, please leave a comment. Comments have to be approved before they are shown here.

Name:

Email(Private):

Message:

Captcha: if i have 3 bananas, and i eat them all, how many bananas did i just eat?