Chlorophyta or Prasinophyta is a taxon of

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 ...

informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it refers to a highly

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

group of ''all'' the green algae within the green plants ( Viridiplantae) and thus includes about 7,000 species of mostly aquatic

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 ...

eukaryotic organisms. In newer classifications, it refers to the sister clade of the

streptophyte Streptophyta (), informally the streptophytes (, from the Greek ''strepto'' 'twisted', for the morphology of the sperm of some members), is a clade of plants. The composition of the clade varies considerably between authors, but the definition ...

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

. The clade Streptophyta consists of the Charophyta in which the Embryophyta (land plants) emerged. In this latter sense the Chlorophyta includes only about 4,300 species. About 90% of all known species live in freshwater. Like the land plants ( embryophytes: bryophytes and tracheophytes), green algae (chlorophytes and charophytes besides embryophytes) contain chlorophyll a and chlorophyll b and store food as

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

in their plastids. With the exception of Palmophyllophyceae, Trebouxiophyceae, Ulvophyceae and

Chlorophyceae The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b. The chloroplast may be discoid, p ...

, which show various degrees of multicellularity, all the Chlorophyta lineages are unicellular. Some members of the group form

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

relationships with

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

, sponges, and cnidarians. Others form symbiotic relationships with fungi to form

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.oogamous or isogamous. All members of the clade have motile flagellated swimming cells. While most species live in freshwater habitats and a large number in marine habitats, other species are adapted to a wide range of land environments. For example, ''Chlamydomonas nivalis'', which causes Watermelon snow, lives on summer alpine snowfields. Others, such as '' Trentepohlia'' species, live attached to rocks or woody parts of trees. '' Monostroma kuroshiense'', an edible green alga cultivated worldwide and most expensive among green algae, belongs to this group.

Ecology

Species of Chlorophyta (treated as what is now considered one of the two main clades of Viridiplantae) are common inhabitants of marine, freshwater and terrestrial environments.Graham LE, Graham JM, Wilcox LW (2009) ''Algae''. 2nd Edition. Benjamin Cummings (Pearson), San Francisco, CA Several species have adapted to specialised and extreme environments, such as deserts, arctic environments, hypersaline habitats, marine deep waters, deep-sea

hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...

s and habitats that experiences extreme changes in temperature, light and salinity. Some groups, such as the Trentepohliales are exclusively found on land. Several species of Chlorophyta live in

symbiosis Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

with a diverse range of

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

s, including fungi (to form

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.ciliates, forams,

cnidarian Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...

s and

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

s. Some species of Chlorophyta are heterotrophic, either free-living or parasitic. Others are mixotrophic bacterivores through phagocytosis. Two common species of the heterotrophic green alga '' Prototheca'' are

pathogenic In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

and can cause the disease protothecosis in humans and animals.

Classifications

Characteristics used for the classification of Chlorophyta are: type of zoid,

mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...

(karyokynesis), cytokinesis, organization level, life cycle, type of gametes,

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

polysaccharides and more recently

genetic data In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding gene ...

Phylogeny

A newer proposed classification follows Leliaert et al. 2011 and modified with Silar 2016, Leliaert 2016 and Lopes dos Santos et al. 2017 for the green algal clades and Novíkov & Barabaš-Krasni 2015 for the land plants clade. Sánchez-Baracaldo et al. is followed for the basal clades. A 2020 paper places the "Prasinodermophyta" (i.e.

Prasinodermophyceae ''Prasinoderma'' is a genus of green algae in the phylum Prasinodermophyta The Prasinodermophyta are a proposed basal Viridiplantae clade, as sister of another clade comprising the Chlorophyta and the Streptophyta. It consists of the Prasinode ...

+ Palmophyllophyceae) as the basal Viridiplantae clade.

Leliaert ''et al''. 2012

Simplified phylogeny of the Chlorophyta, according to Leliaert ''et al''. 2012. Note that many algae previously classified in Chlorophyta are placed here in Streptophyta. * Viridiplantae **Chlorophyta ***core chlorophytes **** Ulvophyceae ***** Cladophorales ***** Dasycladales ***** Bryopsidales ***** Trentepohliales ***** Ulvales- Ulotrichales ***** Oltmannsiellopsidales ****

*****

Oedogoniales The Oedogoniales are an order of filamentous freshwater green algae of the class Chlorophyceae. The order is well-defined and has several unique features, including asexual reproduction with zoospores that possess stephanokont flagella: numerous ...

*****

Chaetophorales Chaetophorales is an order of green algae in the class Chlorophyceae The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of pig ...

*****

Chaetopeltidales Chaetopeltidales are an order of green algae in the class Chlorophyceae The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of ...

***** Chlamydomonadales ***** Sphaeropleales **** Trebouxiophyceae ***** Chlorellales ***** Oocystaceae ***** Microthamniales *****

Trebouxiales The Trebouxiales are an order of green algae in the class Trebouxiophyceae The Trebouxiophyceae are a class of green algae, in the division Chlorophyta. Their circumscription within the green algae is not well established due to the need for ...

*****'' Prasiola'' clade ****

Chlorodendrophyceae Chlorodendrales are an order of green, flagellated, thecate, unicellular eukaryotes, within the green algae class Chlorodendrophyceae.Becker, B., Marin, B. and Melkonian, M. 1994: Structure, composition, and biogenesis of prasinophyte cell coveri ...

*** prasinophytes (paraphyletic) **** Pyramimonadales **** Mamiellophyceae **** Pycnococcaceae **** Nephroselmidophyceae ****

Prasinococcales Prasinococcaceae is a family of 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 (Embryophyte ...

**** Palmophyllales ** Streptophyta *** charophytes **** Mesostigmatophyceae **** Chlorokybophyceae **** Klebsormidiophyceae **** Charophyceae **** Zygnematophyceae **** Coleochaetophyceae *** Embryophyta (land plants)

Pombert ''et al''. 2005

A possible classification when Chlorophyta refers to one of the two clades of the Viridiplantae is shown below. * Class Prasinophyceae T. A. Chr. ex Ø. Moestrup & J. Throndsen * Class

Wille * Class Trebouxiophyceae T. Friedl * Class Ulvophyceae

Lewis & McCourt 2004

* Division Chlorophyta (green algae sensu stricto) ** Subdivision Chlorophytina *** Class

(chlorophytes) **** Order Chlamydomonadales (+ some Chlorococcales + some Tetrasporales + some

Chlorosarcinales Chlamydomonadales, also known as Volvocales, are an order of flagellated or pseudociliated green algae, specifically of the Chlorophyceae.See the NCBIbr>webpage on Chlamydomonadales Data extracted from the Chlamydomonadales can form planar ...

) **** Order Sphaeropleales (sensu Deason, plus ''Bracteacoccus, Schroederia, Scenedesmaceae, Selanastraceae'') **** Order

**** Order

**** Incertae Sedis (''Cylindrocapsa'' clade, ''Mychonastes'' clade) *** Class Ulvophyceae (ulvophytes) **** Order Ulotrichales **** Order Ulvales **** Order Siphoncladales/ Cladophorales **** Order Caulerpales **** Order Dasycladales *** Class Trebouxiophyceae (trebouxiophytes) **** Order

**** Order Microthamniales **** Order Prasiolales **** Order Chlorellales *** Class Prasinophyceae (prasinophytes) **** Order Pyramimonadales **** Order Mamiellales **** Order

Pseudoscourfieldiales Pseudoscourfieldiales is an order of green algae in the class Pyramimonadophyceae. References External links Chlorophyta orders Pyramimonadophyceae Monotypic orders {{green algae-stub ...

**** Order Chlorodendrales **** Incertae sedis (Unnamed clade of coccoid taxa) * Division Charophyta (charophyte algae and embryophytes) ** Class Mesostigmatophyceae (mesostigmatophytes) ** Class Chlorokybophyceae (chlorokybophytes) ** Class Klebsormidiophyceae (klebsormidiophytes) ** Class Zygnemophyceae (conjugates) *** Order Zygnematales (filamentous conjugates and saccoderm desmids) *** Order Desmidiales (placoderm desmids) ** Class Coleochaetophyceae (coleochaetophytes) *** Order Coleochaetales ** Subdivision Streptophytina *** Class Charophyceae (reverts to use of GM Smith) **** Order Charales (charophytes sensu stricto) *** Class

Embryophyceae The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sist ...

(embryophytes)

Hoek, Mann and Jahns 1995

Classification of the Chlorophyta, treated as all green algae, according to Hoek, Mann and Jahns 1995. * Class Prasinophyceae (orders Mamiellales, Pseudocourfeldiales, Pyramimonadales, Chlorodendrales) * Class

(orders Volvocales Tetrasporales">ncluding the Tetrasporales Chlorococcales,

) * Class Ulvophyceae (orders Codiolales, Ulvales) * Class Cladophorophyceae (order Cladophorales) * Class Bryopsidophyceae (orders Bryopsidales, Halimedales) * Class Dasycladophyceae (order Dasycladales) * Class Trentepohliophyceae (order Trentepohliales) * Class

Pleurastrophyceae The Pleurastrophyceae were a formerly recognized class of green algae, in the division Chlorophyta. It was created by Mattox and Stewart in 1984, containing four genera. More recent classifications tend to split the group. On the one hand, ''Te ...

(order Pleurastrales) * '' Incertae sedis'' (order Prasiolales) * Class Klebsormidiophyceae (orders Klebsormidiales, Coleochaetales) * Class Zygnematophyceae (order Zygnematales, Desmidiales) * Class Charophyceae (order Charales) In a note added in proof, an alternative classification is presented for the algae of the class Chlorophyceae: * Class Chlamydophyceae (orders Volvocales, Chlorococcales,

) * Class Oedogoniophyceae (order

) * Class

(order Chlorellales)

Bold and Wynne 1985

Classification of the Chlorophyta and Charophyta according to Bold and Wynne 1985. * Chlorophyta,

(16 orders) ** Volvocales ** Tetrasporales ** Chlorococcales **

** Ulotrichales ** Sphaeropleales **

** Trentepohliales **

** Ulvales ** Cladophorales **

Acrosiphoniales Ulotrichales is an order of green algae in the class Ulvophyceae.See the NCBIbr>webpage on Ulotrichales Data extracted from the Genera unplaced to family (''incertae sedis''): *'' Trichosarcina'' Families * '' Binucleariaceae'' * '' Collin ...

** Caulerpales ** Siphonocladales ** Dasycladales ** Zygnematales * Charophyta, Charophyceae (1 order) ** Charales

Mattox & Stewart 1984

Classification of the Chlorophyta according to Mattox & Stewart 1984: * Micromonadophyceae (similar to Prasinophyceae; Tetraselmidiales transferred to Pleurastrophyceae) * Charophyceae Rabenhorst **

Chlorokybales ''Chlorokybus'' is a multicellular (sarcinoid) genus of basal green algae or charophyte, a soil alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grou ...

** Klebsormidiales ** Zygnematales ** Coleochaetales ** Charales * Ulvophyceae *

** Tetraselmidiales ** Pleurastrales *

Wille in Warming ** Chlamydomonadales ** Volvocales ** Chlorococcales ** Sphaeropleales **

Fott 1971

Classification of the Chlorophyta according to Fott 1971. *Class

:*Order Volvocales :*Order Tetrasporales :*Order Chlorococcales :*Order Ulotrichales ::*Suborder Chlorosarcineae ::*Suborder Ulotrichineae ::*Suborder Oedogoniineae ::*Suborder Chaetophorineae :*Order Siphonocladales :*Order Bryopsidales *Class

Conjugatophyceae Zygnematophyceae (or Conjugatophyceae) is a class of green algae in the paraphylum streptophyte algae, also referred to as Charophyta, consisting of more than 4000 described species. It contains five orders: the Spirogloeales, the Serritaeniales ...

*Class Charophyceae

Round 1971

Classification of the Chlorophyta and related algae according to Round 1971. * "

" ** Euglenophyta ** Prasinophyta ** Charophyta ** Chlorophyta ***

Zygnemaphyceae Zygnematophyceae (or Conjugatophyceae) is a class of green algae in the paraphylum streptophyte algae, also referred to as Charophyta, consisting of more than 4000 described species. It contains five orders: the Spirogloeales, the Serritaeniales, ...

; orders Mesotaeniales, Zygnematales, Gonatozygales, Desmidiales) *** Oedogoniophyceae (order

) *** Bryopsidophyceae **** Hemisiphoniidae (orders Cladophorales, Sphaeropleales,

**** Cystosiphoniidae (orders Dasycladales, Siphonocladales, Chlorochytriales) **** Eusiphoniidae (orders Derbesiales, Codiales, Caulerpales, Dichotomosiphonales, Phyllosiphonales) ***

**** orders Chlamydomonadales, Volvocales, Polyblepharidales, Tetrasporales, Chlorodendrales,

, Chlorococcales **** orders Ulotrichales, Codiolales, Ulvales, Prasiolales, Cylindrocapsales, Microsporales **** orders

, Coleochaetales, Trentepohliales, Pleurococcales, Ulvellales

Smith 1938

Classification of the Chlorophyta according to Smith 1938: *Class 1.

::*Order 1. Volvocales ::::*Family 1. Chlamydomonadaceae ::::*Family 2. Volvocaceae ::*Order 2. Tetrasporales ::*Order 3. Ulotrichales ::::*Family 1. Ulotrichaceae ::::*Family 2.

Microsporaceae Microsporaceae are a family of green algae in the class Chlorophyceae.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes ...

::::*Family 3. Cylindrocapsaceae ::::*Family 4.

Chaetophoraceae Chaetophoraceae is a family of green algae in the order Chaetophorales. Genera * '' Arthrochaete'' * '' Caespitella'' * '' Cedercreutziella'' * '' Chaetomnion'' * '' Chaetonemopsis'' * '' Chaetophora'' * '' Chloroclonium'' * '' Chlorofilum'' * ...

::::*Family 5. Protococcaceae ::::*Family 6.

Coleochaetaceae Coleochaetaceae is a family of algae. It is the only family in the Coleochaetales, an order of parenchymous charophyte algae, that includes some of the closest multicellular relatives of land plants. They questionably include the fossil genus ...

::::*Family 7. Trentepohliaceae ::*Order 4. Ulvales ::::*Family 1. Ulvaceae ::::*Family 2

Schizomeridaceae Schizomeridaceae is a family of algae in the order Chaetophorales.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of ...

::*Order 5. Schizogoniales ::::*Family Schizogoniaceae ::*Order 6. Cladophorales ::::*Family 1. Cladophoraceae ::::*Family 2. Sphaeropleaceae ::*Order 7.

::::*Family Oedogoniaceae ::*Order 8. Zygnematales ::::*Family 1. Zygnemataceae ::::*Family 2. Mesotaeniaceae ::::*Family 3. Desmidiaceae ::*Order 9. Chlorococcales ::::*Family 1. Chlorococcaceae ::::*Family 2.

Endosphaeraceae Chlorochytriaceae is a family of algae within the order Chlamydomonadales Chlamydomonadales, also known as Volvocales, are an order of flagellated or pseudociliated green algae, specifically of the Chlorophyceae.See the NCBIbr>webpage on C ...

::::*Family 3. Characiaceae ::::*Family 4.

Protosiphonaceae Protosiphonaceae is a family of chlorophyte green algae, in the order Chlamydomonadales. Genera , AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both marine and freshwater, as well as sea-grass. Hi ...

::::*Family 5. Hydrodictyaceae ::::*Family 6. Oöcystaceae ::::*Family 7. Scenedesmaceae ::*Order 10. Siphonales ::::*Family 1. Bryopsidaceae ::::*Family 2. Caulerpaceae ::::*Family 3. Halicystaceae ::::*Family 4. Codiaceae ::::*Family 5.

Derbesiaceae Derbesiaceae are a family of 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) ...

::::*Family 6. Vaucheriaceae ::::*Family 7. Phyllosiphonaceae ::*Order 11. Siphonocladiales ::::*Family 1. Valoniaceae ::::*Family 2. Dasycladaceae *Class 2. Charophyceae ::*Order Charales ::::*Family

Characeae Characeae is a family of freshwater green algae in the order Charales, commonly known as stoneworts. They are also known as brittleworts or skunkweed, from the fragility of their lime-encrusted stems, and from the foul odor these produce when step ...

Research and discoveries

In February 2020, the fossilized remains of green algae, named ''Proterocladus antiquus'' were discovered in the northern province of

Liaoning Liaoning () is a coastal province in Northeast China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost ...

, China. At around a billion years old, it is believed to be one of the oldest examples of a multicellular chlorophyte.

Ecology

Classifications

Phylogeny

Leliaert ''et al''. 2012

Pombert ''et al''. 2005

Lewis & McCourt 2004

Hoek, Mann and Jahns 1995

Bold and Wynne 1985

Mattox & Stewart 1984

Fott 1971

Round 1971

Smith 1938

Research and discoveries

References

Further reading