''Nostoc commune'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

cyanobacterium Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blue ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Nostocaceae The Nostocaceae are a family of cyanobacteria that forms filament-shaped colonies enclosed in mucus or a gelatinous sheath. Some genera in this family are found primarily in fresh water (such as ''Nostoc''), while others are found primarily in ...

. Common names include star jelly, witch's butter, mare's eggs, fah-tsai and facai. It is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Nostoc ''Nostoc'', also known as star jelly, troll’s butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch’s jelly, is the most common genus of cyanobacteria found in vari ...

'' and is

cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...

in distribution.

Description

''Nostoc commune'' is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

species of cyanobacterium. It initially forms a small, hollow gelatinous globule which grows and becomes leathery, flattened and convoluted, forming a gelatinous mass with other colonies growing nearby. Inside the thin sheath are numerous unbranched hair-like structures called

trichome Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a pla ...

s formed of short cells in a string. The cells are bacteria and thus have no nucleus nor internal membrane system. To multiply, they form two new cells when they divide by

binary fission Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that t ...

. Along the trichomes, larger specialist nitrogen-fixing cells called

heterocyst Heterocysts or heterocytes are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as '' Nostoc punctiforme'', ''Cylindrospermum stagnale'', and ''Anabaena sphaerica''. They fix nitrogen fr ...

s occur between the ordinary cells. When wet, ''Nostoc commune'' is bluish-green, olive green or brown but in dry conditions it becomes an inconspicuous, crisp brownish mat.

Distribution and habitat

''Nostoc commune'' is found in many countries around the world. It is able to survive in extreme conditions in polar regions and arid areas. It is a terrestrial or freshwater species and forms loose clumps on soil, gravel and paved surfaces, among mosses and between cobbles. In Singapore, ''Nostoc commune'' is found growing on alkaline soils, in

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estua ...

, in

paddy field A paddy field is a flooded field (agriculture), field of arable land used for growing Aquatic plant, semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in sout ...

s, on cliffs and on wet rocks.

Biology

''Nostoc commune'' can fix nitrogen from the atmosphere and can therefore live in locations where no nitrogenous compounds are available from the substrate. ''Nostoc commune'' contains

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

pigments and the energy storing photosystems in membrane structures called

thylakoids Thylakoids are membrane-bound compartments inside chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis. Thylakoids consist of a thylakoid membrane surrounding a thylakoid lumen. Chloroplast th ...

located in cytoplasm of the cells. It also contains pigments that absorb long and medium wavelength

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

radiation, which enables it to survive in places with high levels of radiation. Under adverse conditions, ''Nostoc commune'' can remain dormant for an extended period of time and revive when conditions improve and water becomes available. The desiccated colony is resistant to heat and to repeated patterns of freezing and thawing and produces no oxygen while dormant. It has been found that extracellular polysaccharides are vital to its stress tolerance and ability to recover. ''Nostoc commune'' can occur in pockets in the

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

of hornworts such as '' Phaeoceros''.

Uses

''Nostoc commune'' is eaten as a salad in the Philippines and is also eaten in Indonesia, Japan and China. In Taiwan, it is nicknamed 雨來菇 ''yǔ lái gū'' (meaning "post-rain mushroom"). ''Nostoc commune'' var. ''flagelliforme'' is known as 发菜 ''fàcài'' in China which forms part of the food traditionally served at the

Lunar New Year Lunar New Year is the beginning of a calendar year whose months are moon cycles, based on the lunar calendar or lunisolar calendar. The Lunar New Year as a celebration is observed by numerous cultures. It is also named " Chinese New Year" becau ...

. Research indicates that consumption of ''Nostoc commune'' var. ''sphaeroides'', in addition to consumption of other cyanobacteria, may be beneficial by means of an anti-inflammatory mechanism.

References

{{Taxonbar, from=Q11286530 Nostocaceae Species described in 1753 Bacteria described in 1753 Taxa named by Carl Linnaeus