Skip to main content


Azollaceae A specialized family of free-floating, aquatic ferns of uncertain affinities. The branched stems bear roots, and 2-lobed, overlapping leaves. Sori bear either microsporangia or megasporangia. The megasporangia are each provided with floats; microspores are numerous and grouped together into ‘massulae’ which bear barbed hairs (glochidia) that hook on to the megaspores. The leaves have a basal cavity inhabited by a cyanobacterium (Anabaena azollae) which fixes nitrogen. There is 1 genus, Azolla, with 6 species, of tropical and warm temperate distribution in America and Asia. They are not native in Europe, but are naturalized there.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Azollaceae." A Dictionary of Plant Sciences. . 22 Mar. 2019 <>.

"Azollaceae." A Dictionary of Plant Sciences. . (March 22, 2019).

"Azollaceae." A Dictionary of Plant Sciences. . Retrieved March 22, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.