|Photo of N. azollae|
|Class:||see taxonomic note|
Nostoc can be found in soil, on moist rocks, at the bottom of lakes and springs (both fresh- and saltwater), and rarely in marine habitats. It may also grow symbiotically within the tissues of plants, such as the evolutionarily ancient angiosperm Gunnera and the hornworts (a group of bryophytes), providing nitrogen to its host through the action of terminally differentiated cells known as heterocysts. These bacteria contain photosynthetic pigments in their cytoplasm to perform photosynthesis.
- N. azollae
- N. caeruleum
- N. carneum
- N. comminutum
- N. commune, Koxianmi (Chinese)
- N. ellipsosporum
- N. flagelliforme
- N. linckia
- N. longstaffi
- N. microscopicum
- N. muscorum
- N. paludosum
- N. pruniforme
- N. punctiforme
- N. sphaericum
- N. sphaeroides
- N. spongiaeforme
- N. verrucosum
When it is on the ground, a nostoc colony is ordinarily not seen; but after a rain it swells up into a conspicuous jellylike mass, which was once thought to have fallen from the sky; hence the popular names, star jelly, troll’s butter, witch's butter (not to be confused with the fungus Tremella mesenterica), and witch’s jelly.
Containing protein and vitamin C, Nostoc species are cultivated and consumed as a foodstuff, primarily in Asia. The N. flagelliforme and N. commune varieties are consumed in China, Japan and Java, N. commune is also consumed in the Andes. The preferred variety in Central Asia is N. ellipsosporum.
A research team from the biochemistry department of the Chinese University of Hong Kong said that international research has shown that fat choy (Nostoc flagelliforme), besides having no nutritional value, has also been found to contain Beta-methylamino L-alanine (BMAA), a toxic amino acid that could affect the normal functions of nerve cells. Professor Chan King-ming of the team told the media that eating fat choy could lead to degenerative diseases such as Alzheimer's, Parkinson's, and dementia.
- Potts, M. (1997). "Etymology of the Genus Name Nostoc (Cyanobacteria)" (pdf). International Journal of Systematic Bacteriology 47 (2): 584. doi:10.1099/00207713-47-2-584.
- Abbott, I. A. (1989). "Food and food products from seaweeds". In Lembi, C. A.; Waaland, J. R. Algae and human affairs. Cambridge University Press, Phycological Society of America. p. 141. ISBN 978-0-521-32115-0.
- Weird Words: Nostoc on World Wide Words
- Thomas, R. J.; Bevan, G. A.; Donovan, P. J. (2003). Geiriadur Prifysgol Cymru. Caerdydd (Cardiff): Gwasg Prifysgol Cymru. ISBN 978-0-7083-1806-5.
- The standard.com.hk[dead link]
- http://machaut.uchicago.edu/cgi-bin/WEBSTER.sh?WORD=nostoc 1913 Webster's Dictionary
- Davidson, Alan. Oxford Companion to Food (1999), "Nostoc". ISBN 0-19-211579-0