Nostoc


Nostoc is a genus of cyanobacteria found in various environments that forms colonies composed of filaments of cells in a gelatinous sheath.
The name Nostoc was coined by Paracelsus.
Nostoc can be found in soil, on moist rocks, at the bottom of lakes and springs, 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, 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.

Species

Nostoc is a member of the family Nostocaceae of the order Nostocales. Species include:
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, and witch’s jelly.

Culinary use

Containing protein and vitamin C, Nostoc species are cultivated and consumed as a foodstuff, primarily in Asia. The species N. flagelliforme and N. commune are consumed in China, where it was used to survive famines. The preferred variety in Central Asia is N. ellipsosporum.

Citations

General sources