
1) Alga
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https://www.crosswordclues.com/clue/anabaena

Anabaena is a genus of filamentous cyanobacteria that exists as plankton. It is known for its nitrogen fixing abilities, and they form symbiotic relationships with certain plants, such as the mosquito fern. They are one of four genera of cyanobacteria that produce neurotoxins, which are harmful to local wildlife, as well as farm animals and pets. ...
Found on
http://en.wikipedia.org/wiki/Anabaena

genus of nitrogen-fixing blue-green algae with beadlike or barrel-like cells and interspersed enlarged spores (heterocysts), found as plankton in ...
Found on
http://www.britannica.com/eb/a-z/a/66

<bacteria> A genus of Cyanobacteria that forms filamentous colonies with specialised cells, capable of nitrogen fixation. Ecologically important in wet tropical soils and forms symbiotic associations with the fern Azolla. ... (18 Nov 1997) ...
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http://www.encyclo.co.uk/local/20973

A genus of Cyanobacteria that forms filamentous colonies with specialized cells (heterocysts), capable of nitrogen fixation. Ecologically important in wet tropical soils and forms symbiotic associations with the fern Azolla .
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http://www.encyclo.co.uk/visitor-contributions.php

Type: Term Pronunciation: an′ă-bē′nă Definitions: 1. A genus of Cyanobacteria found in fresh water that can cause odor in water supplies; although not invasive pathogens, they produce potent saxitoxinlike neurotoxins that can poison farm animals that ingest heavily infected pond water.
Found on
http://www.medilexicon.com/medicaldictionary.php?t=3242

any of the freshwater algae of the genus Anabaena, commonly occurring in masses and often contaminating drinking water, giving it a fishy odor and taste.
Found on
https://www.infoplease.com/dictionary/anabaena
No exact match found.