Azolla filiculoides Lam., Encycl. 1(1): 343 1783. (Syn. Azolla arbuscula Desv.; Azolla magellanica Willd.; Azolla squamosa Molina);
New World: Alaska, Argentina Northeast, Argentina Northwest, Argentina South, Arizona, Arkansas, Bolivia, Brazil North, Brazil Northeast, Brazil South, Brazil Southeast, Brazil West-Central, British Columbia, California, Chile Central, Chile North, Chile South, Colombia, Colorado, Costa Rica, Dominican Republic, Ecuador, El Salvador, Galápagos, Guatemala, Guyana, Honduras, Illinois, Iowa, Kansas, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Northwest, Mexico Southeast, Mexico Southwest, Minnesota, Missouri, Nebraska, Nevada, New Mexico, Nicaragua, Oklahoma, Oregon, Panamá, Paraguay, Peru, Texas, Tristan da Cunha, Uruguay, Utah, Venezuela, Venezuelan Antilles, Washington, Wisconsin; Introduced into: Albania, Assam, Austria, Baltic States, Bangladesh, Belgium, Bulgaria, Canary Is., Cape Provinces, China Southeast, Czechoslovakia, Denmark, France, Free State, Germany, Great Britain, Greece, Hawaii, Hungary, India, Ireland, Italy, Japan, Jawa, Korea, KwaZulu-Natal, Lesotho, Malaya, Morocco, Mozambique, Namibia, Nansei-shoto, Nepal, Netherlands, New York, Northern Provinces, Pakistan, Palestine, Poland, Portugal, Romania, Sardegna, Sicilia, Spain, Swaziland, Sweden, Tadzhikistan, Taiwan, Turkey, Turkey-in-Europe, West Himalaya, Yugoslavia, Zimbabwe as per POWO;

Azolla filiculoides (Water Fern) is a species of Azolla, native to warm temperate and tropical regions of the Americas as well as most of the old world including Asia and Australia.

It is a floating aquatic fern, with very fast growth, capable of spreading over lake surfaces to give complete coverage of the water in only a few months. Each individual plant is 1-2 cm across, green tinged pink, orange or red at the edges, branching freely, and breaking into smaller sections as it grows. It is not tolerant of cold temperatures, and in temperate regions it largely dies back in winter, surviving by means of submerged buds. Like other species of Azolla, it can fix nitrogen from the air.
The species has been introduced to many regions of the Old World, grown for its nitrogen-fixing ability which can be utilized to enhance the growth rate of crops grown in water like rice, or by removal from lakes for use as green manure. It has become naturalized, sometimes also an invasive species, in several regions, including western Europe, southern Africa, tropical Asia, Australia (where it is considered native), and New Zealand.
(From Wikipedia on 13.11.14)


Azolla pinnata R. Br.:
This might be Azolla pinnata R. Br., recorded on 24-Aug.-2012 at Gobra (Hooghly), West Bengal.

Related links :-

If it is Azolla pinnata, as per distribution it may be Azolla pinnata subsp. asiatica R.M.K.Saunders & K.Fowler compared to distribution of Azolla pinnata subsp. africana (Desv.) R.M.K.Saunders & K.Fowler and  Azolla pinnata subsp. pinnata

No it isn’t A. pinnata at all – no wild guesses please, let’s look at it, and the main literature and try to work it out!
Actually you can see that instead of a pinnate-branching, triangular plant-body (as in A. pinnata of any subspecies) the branches are radiating.
It is A. filiculoides, which is a common adventive species all over India now  and has been present nearly 50 years. I detailed it in the Ferns and Fern-allies of Nepal vol. 1 (but a poor photo) better photos, showing the growth-habit of both species for comparison are in my Taxonomic Revision of 300 Indian Subcontinental Pteridophytes (2008: 511-513), inc. from the IBG, Howrah.
Within A. filiculoides there are two closely related subspecies (or species if preferred) subsp. filiculoides, whose origin was from Europe and subsp. cristata, originally the American plant. Nowadays, as A. filiculoides has spread all over the place (to assist rice-cultivation etc., or escaped), both subspecies are also mixed up and both occur in India.  They differ in the number of cells in the glochidia in the spore-bearing bodies, and in the number of leaf-hair cells (microscope needed).
I can’t hazard a guess which subspecies from this, but the one at the Indian Botanic Garden was determined by two expert Profs., Evrard and Van Hove, Louvain, Belgium, as subsp. filiculoides.


Azolla of Indonesia : 14 posts by 2 authors. Attachments (2)
Could you help me to id our fern please. Is it Azolla microphylla or A. filiculoides? Thank you.

More plants need to be shown to see the growth pattern properly – show four or five plants if you want it identified for certain.  But it looks more like A. filiculoides than the common native A. pinnata subsp. asiaticaA. filiculoides is widely adventive in India and Asia and both the originally American plant, subsp. cristata, and the European subsp. filiculoides are here.
To confirm you need to study the hairs on the leaf and the number of cells in the glochidia of fertile sorocarps with a microscope.

I hope, the following picture can make it more clearly. Attachments (1)

No, it makes it less clear – in my book (2008) where I illustrated them clearly by good photos, I explain that it is the direction of the growth of the branches that easily decides between the filiculoides aggregate and pinnata aggregate.  Thus I need to see a photo with several or say 10 individual fronds, undisturbed on the water surface.

A reply from …: Azolla caroliniana. Could … make a comment please.

A. carolineana is know definitively known to be a synonym of A. filiculoides.  Can I see several plants (say 5 to 10) in one photo, please?  But I’ll be travelling for two days to get home to Nepal as from tomorrow, and will then need a couple of days to get my internet set up again – so can’t reply absolutely straight away, my apologies.

The following image is the Azolla that you need to see. Could you please validate. Thank you. Attachments (1)

Oh yes – that’s typical filiculoides, you can see the beautiful radiate branching pattern, not pinnate.  It is adventive there (as also over here in Nepal and India), but which subspecies of the filiculoides group it is, would need careful microsopic checking of the short, stumpy hairs on the leaves and the number of cells in the hairs of the fertile glochidia.  Otherwise send some to Prof C. van Hove, Universite Catholique de Louvain, Belgium [I have his e-mail address somewhere, but would take time. It is presumably subsp. filiculoides or subsp. cristata, previously treated as species.

Fwd: For ID- N220116 : 4 posts by 2 authors. Attachments (2)
Can anyone ID the photograph?
Time of photograph: January 2016
Location: Renuka Ji Lake
Elevation: Around 650m
District: Sirmour
State: Himachal Pradesh

This plant is Azolla spp., a pteridophyte, may be A. pinnata

This is Azolla filiculoides, which can be seen from its radiate thallus-shape, not A. pinnata subsp. asiatica, which has a more triangular shape and is pinnate, not radiate.
A. filiculoides is adventive in India, presumably introduced deliberately in connection with rice-cultivation due to the nitrogen fixation of the associated Blu-green Algae, but in recent decades it has become quite widespread throughout. There are two very close subspecies, subsp. cristata (originally of American origin), which is confirmed from Kashmir (where it used not to occur some 30 years ago), and subsp. filiculoides (originally of European and Old World origin), which is confirmed from Nepal and Calcutta.
The two are very closely similar and require careful microscopic examination of the number of cells in the little leaf-hairs and in the glochidia, hairs on the reproductive sporangia. The full distribution (so far) of the two subspecies in India is not further known pending study of more populations.


YAMUNA::11042012::SL 1:
I found these plant near river Yamuna bank , Wazirabad, Delhi
I am totally confuse about its classification. I even dont understand wether it is an angiosperm or gymnosperm. Please identify these plants with reasons.

It is Azolla pinnata R. Br.
A water fern, must be a dried pond you have photographed from. It is commonly used as green manure especially in Rice fields because fronds inhabit symbiotic alga Anabaena.

If it is Azolla pinnata, as per distribution it may be Azolla pinnata subsp. asiatica R.M.K.Saunders & K.Fowler compared to distribution of Azolla pinnata subsp. africana (Desv.) R.M.K.Saunders & K.Fowler and  Azolla pinnata subsp. pinnata

Too crowded – difficult to see shape, might be A. filiculoides rather than pinnata.



POWO  The Plant List Ver.1.1  Tropicos  Wikipedia  

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