''Chara'' is a

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 ...

charophyte Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly from terre ...

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

in the family Characeae. They are multicellular and superficially resemble land plants because of

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

-like and

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

-like structures. They are found in freshwater, particularly in limestone areas throughout the northern temperate zone, where they grow submerged, attached to the muddy bottom. They prefer less oxygenated and hard water and are not found in waters where mosquito larvae are present. They are covered with calcium carbonate deposits and are commonly known as stoneworts.

Cyanobacteria 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, blu ...

have been found growing as epiphytes on the surfaces of ''Chara'', where they may be involved in fixing

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

, which is important to plant nutrition. Cyanobacteria growing as epiphytes on Chara species

Structure

The branching system of ''Chara'' species is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately.Round, F.E. 1965.''The Biology of the algae.'' Ernest Arnold. The main axes bear whorls of branches in a superficial resemblance to ''

Equisetum ''Equisetum'' (; horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of ferns, which reproduce by spores rather than seeds. ''Equisetum'' is a "living fossil", the only living genus of the entire subclass Eq ...

'' (a vascular plant). They are typically anchored to the

littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

substrate by means of branching underground

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be unic ...

s. ''Chara'' plants are rough to the touch because of deposited

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

salts on the cell wall. The metabolic processes associated with this deposition often give ''Chara ''plants a distinctive and unpleasant smell of

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

Morphology

The plant body is a

gametophyte A gametophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has on ...

. It consists of the main axis (differentiated into nodes and internodes), dimorphic branches (long branch of unlimited growth and short branches of limited growth), rhizoids (multicellular with oblique septa) and stipulodes (needle-shaped structures at the base of secondary laterals).

Reproduction

''Chara'' reproduces vegetatively and sexually. Vegetative reproduction takes place by

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...

s, amylum stars and secondary

protonema A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage of development of the gametophyte (the haploid phase) in the life cycle of mosses. When a moss first grows from a spore, it starts as a ''germ tube'', ...

ta. The sex organs are a multicellular and jacketed globule or antheridium (male) and nucule or archegonium (female). The antheridia and archegonia may occur on separate plants (

dioicy Dioicy () is a sexual system where archegonia and antheridia are produced on separate gametophytes. It is one of the two main sexual systems in bryophytes. Both dioicous () and monoicous gametophytes produce gametes in gametangia by mitosis ra ...

), together on the same plant (conjoined monoicy) or separately on the same plant (sejoined monoicy). After fertilization, the zygote develops into an

oospore An oospore is a thick-walled sexual spore that develops from a fertilized oosphere in some algae, fungi, and oomycetes. They are believed to have evolved either through the fusion of two species or the chemically-induced stimulation of mycelia, ...

Species

Distribution

''Chara'' has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

, from 69 degrees north in northern Norway to about 49 degrees south in

Kerguelen Islands The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...

(Pal et al., 1962). About 27 species are found in

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

.Soni, N.K. Fundamentals of Botany Vol. 1, Tata McGraw-Hill Education, p72, There are about 40 species of Chara in Europe, where they are commonly found in the specific

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

-type designated as H3140 (hard oligo-mesotrophic waters with benthic vegetation of ''Chara spp'' h1) in the

Natura 2000 Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectively ...

plans of the European Union. Although this habitat is found all across Europe, it is threatened and to be protected and preserved.

The Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

are home to 20 species of ''Chara'', growing in lakes and ponds of the habitat-type H3140. The H3140 habitats in the Netherlands, are considered important in the overall preservation efforts and therefore also for the ''Chara'' species in general.

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

. Here, many former ''Chara'' habitats (H3140) have been polluted by either toxins or excessive amounts of nutrients (in particular

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phospho ...

s and

), but a few large lakes and ponds remain. ''Chara'' is found growing in the very clean

hard water Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, which are largely made up of calcium and magnesium carbonates, bicarbo ...

lakes of

Thy National Park Thy National Park ( da, Nationalpark Thy) is a national park area in Thy, Denmark, opened to the public on 22 August 2008. It is located in Northwest Jutland, along the coast from Hanstholm to Agger Tange and it spans north to south and east to ...

like Nors Sø for example. Tissø lake (fourth-largest lake in Denmark) is also a H3140 habitat and contains ''Chara'' species.Natura 2000 basic analysis 2015-2021 for Hanstholm Reservatet, Hanstholm Knuden, Nors Sø and Vandet Sø
Danish Nature Agency 2013

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

:- Co. Galway. Eglinton Canal '' Chara virgata'' Kütz., '' Chara rudis'' (A.Braun) Leonhardii and '' Nitella flexilis'' (L.) C.Agardh.Pybus, C. and O'Halloran, P. 2009. Distribution of some submerged aquatic macrophytes in Eglinton Canal, Galway. ''Ir. Nat. J.'' 30: 51 - 53

References

{{Authority control Charophyta Charophyta genera Extant Silurian first appearances