Viridiplantae (; kingdom

Plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

ae ''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

'') is a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

of around 450,000–500,000 species of

eukaryotic The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

organisms, most of which obtain their energy by

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

. The green plants are

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

-bearing

autotroph An autotroph is an organism that can convert Abiotic component, abiotic sources of energy into energy stored in organic compounds, which can be used by Heterotroph, other organisms. Autotrophs produce complex organic compounds (such as carbohy ...

s that play important

primary production In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through ...

roles in both

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

and

aquatic ecosystem An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environ ...

s. They include

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

, which are primarily aquatic, and the land plants (

embryophyte The embryophytes () are a clade of plants, also known as Embryophyta (Plantae ''sensu strictissimo'') () or land plants. They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands. Embryophy ...

ae ''

sensu strictissimo ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

''), which emerged within freshwater green algae. Green algae traditionally excludes the land plants, rendering them a

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

group, however it is

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

ally accurate to think of land plants as a special clade of green algae that evolved to thrive on dry land. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them. Viridiplantae species all have

cell Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a de ...

s with

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

in their

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

s, and primary chloroplasts derived from

endosymbiosis An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualism (biology), mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), whi ...

with

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

that contain chlorophylls a and b and lack

phycobilin Phycobilins (from Greek: '' (phykos)'' meaning "alga", and from Latin: ''bilis'' meaning "bile") are light-capturing bilins found in cyanobacteria and in the chloroplasts of red algae, glaucophytes and some cryptomonads (though not in green a ...

s. Corroborating this, a basal

phagotroph Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis i ...

Archaeplastida The Archaeplastida (or kingdom Plantae '' sensu lato'' "in a broad sense"; pronounced ) are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group glaucophytes. It als ...

group has been found in the Rhodelphydia. In some classification systems, the group has been treated as a kingdom, under various names, e.g. Viridiplantae, Chlorobionta, or simply

ae, the latter expanding the traditional plant kingdom of

s to include the

. Adl'' et al.'', who produced a classification for all eukaryotes in 2005, introduced the name Chloroplastida for this group, reflecting the group having primary chloroplasts. They rejected the name Viridiplantae on the grounds that some of the species are not

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s as understood traditionally. Together with

Rhodophyta Red algae, or Rhodophyta (, ; ), make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 recognized species within over 900 genera amidst ongoing taxonomic revisions. ...

glaucophyte The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of unicellular algae found in freshwater and moist terrestrial environments, less common today than they were during the Proterozoic. The stated number of speci ...

s and other basal groups, Viridiplantae belong to a larger clade called

which in itself is sometimes described as

ae ''

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

''.

Evolution

Taxonomy

Leliaert ''et al'', 2012 propose the following simplified taxonomy of the Viridiplantae. * Viridiplantae **

Chlorophyta Chlorophyta is a division of green algae informally called chlorophytes. Description Chlorophytes are eukaryotic organisms composed of cells with a variety of coverings or walls, and usually a single green chloroplast in each cell. They are ...

*** core chlorophytes ****

Ulvophyceae The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of Ultrastructure, ultrastructural morphology, Biological life cycle, life cycle and molecular phylogenetics, molecular phylogenetic data. The sea lettu ...

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Cladophorales Cladophorales are an order of green algae, in the class Ulvophyceae. The earliest known representative is ''Proterocladus antiquus'' from the Mesoproterozoic-Neoproterozoic boundary in North China. The order Cladophorales consists of filamentou ...

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Dasycladales Dasycladales is an Order (biology), order of large unicellular green algae in the class Ulvophyceae. It contains two families, the Dasycladaceae and the Polyphysaceae. These single celled algae are from 2 mm to 200 mm long. They liv ...

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Bryopsidales Bryopsidales is an order of green algae, in the class Ulvophyceae. It is a diverse group of mostly marine macroalgae. Characteristics The thallus is filamentous, highly branched, and may be packed into a mass. It is coenocytic, having multi-nu ...

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Trentepohliales Trentepohliaceae are a family (biology), family of green algae, and the only family in the order Trentepohliales. It is a member of the Ulvophyceaen green algae. The family is characterized by traits like net-like chloroplasts without pyrenoids, ...

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Ulvales Ulvales is an order of green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charoph ...

Ulotrichales 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 ...

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Oltmannsiellopsidales Oltmannsiellopsidales is an order of green algae in the class Ulvophyceae.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health ...

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Chlorophyceae The Chlorophyceae, also known as chlorophycean algae, are one of the classes of green algae, within the phylum Chlorophyta. They are a large assemblage of mostly freshwater and terrestrial organisms; many members are important primary producers i ...

***** Oedogoniales *****

Chaetophorales Chaetophorales is an order of green algae in the class Chlorophyceae. Algae in the order Chaetophorales consist of filamentous, branched algae. The thalli have two parts, a prostrate and upright section and the filaments are variously branched. T ...

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Chaetopeltidales Chaetopeltidales are an order of green algae in the class Chlorophyceae. In comparison to other chlorophycean orders, the order is species-poor and was circumscribed relatively recently, in 1994; the key ultrastructural features include having ...

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Chlamydomonadales 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 o ...

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Sphaeropleales Sphaeropleales is an order of green algae that used to be called Chlorococcales. The order includes some of the most common freshwater plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphe ...

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Trebouxiophyceae The Trebouxiophyceae, also known as trebouxiophytes, are a class of green algae, in the division Chlorophyta. Members of this class are single-celled, colonial, or multicellular and are found in freshwater, terrestrial or marine habitats worldwid ...

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Chlorellales The Chlorellales are an order of green algae in the class Trebouxiophyceae. The Chlorellales include mostly freshwater or terrestrial (rarely marine), coccoid algae. Molecular phylogenetic studies mostly tend to find Chlorellales to consist of t ...

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Oocystaceae Oocystaceae is a family (biology), family of green algae, in the class Trebouxiophyceae. Molecular phylogenetic studies mostly (but not always) place the family in the order Chlorellales, as sister to Chlorellaceae. The Type (biology), type genus ...

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Microthamniales Microthamniaceae is a family of green algae in the class Trebouxiophyceae. It is the only family in the order Microthamniales. Currently, there are two accepted genera within the family, ''Coleochlamys'' and ''Microthamnion''. The two genera are ...

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Trebouxiales The Trebouxiales are an order (biology), order of green algae in the Class (biology), class Trebouxiophyceae. References

Trebouxiales, Chlorophyta orders {{green algae-stub ...

***** ''

Prasiola ''Prasiola'' is a genus of macroscopic green algae, found in a variety of habitats ranging from terrestrial, freshwater, to marine. The genus has a cosmopolitan distribution, ranging from the Arctic to the Antarctic. Plants belonging to the genu ...

'' clade ****

Chlorodendrophyceae Chlorodendrales are an order of green, flagellated, thecate, unicellular eukaryotes, within the green algae class Chlorodendrophyceae.See the NCBIbr>webpage on Chlorodendrales Data extracted from the Prasinophyceae are defined by their cellular ...

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Chlorodendrales Chlorodendrales are an order of green, flagellated, thecate, unicellular eukaryotes, within the green algae class Chlorodendrophyceae.See the NCBIbr>webpage on Chlorodendrales Data extracted from the Prasinophyceae are defined by their cellula ...

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Pedinophyceae Pedinophyceae is a class of green algae in the division Chlorophyta Chlorophyta is a division of green algae informally called chlorophytes. Description Chlorophytes are eukaryotic organisms composed of cells with a variety of coverings ...

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prasinophytes The prasinophytes are a group of unicellular green algae. Prasinophytes mainly include marine planktonic species, as well as some freshwater representatives.Sym, S. D. and Pienaar, R. N. 1993. The class Prasinophyceae. In Round, F. E. and Chapman ...

(paraphyletic) ****

Pyramimonadales Pyramimonadales are an order of green algae in the Chlorophyta. The chloroplasts of phototrophic euglenids probably came from endosymbiosis with a member of this order. Taxonomy * Family Polyblepharidaceae Dangeard 1888 ** Genus '' Amphoraemona ...

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Mamiellophyceae Mamiellophyceae is a class of green algae in the division Chlorophyta. The class contains three orders containing 25 species. * Order Dolichomastigales Marin & Melkonian (7 species) * Order Mamiellales Moestrup (13 species) * Order Monomas ...

**** Pycnococcaceae **** Nephroselmidophyceae ****

Prasinococcales ''Prasinococcus'' is a monotypic genus of green algae, containing the only species ''Prasinococcus capsulatus'', in the monotypic family Prasinococcaceae. This unicellular algal species was discovered in 1990 in the West Pacific Ocean and has cha ...

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Palmophyllales The Palmophyllales are a deep-branching order of thalloid green alga, containing the single family Palmophyllaceae. They possibly form a sister group to the Chlorophyta. They survive today in deep waters, and can be found at 210 meters below the ...

Streptophyta 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 e ...

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Charophytes Charophyta () is a Paraphyly, paraphyletic group of freshwater green algae, called charophytes (), sometimes treated as a Division (taxonomy), division, yet also as a Division (taxonomy), superdivision. The terrestrial plants, the Embryophyta em ...

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Mesostigmatophyceae The Mesostigmatophyceae are a class of basal green algae found in freshwater. In a narrow circumscription, the class contains a single genus, '' Mesostigma''. AlgaeBase AlgaeBase is a global species database of information on all groups of a ...

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Mesostigma ''Mesostigma'' is a genus of unicellular biflagellate freshwater green algae, with a single species ''Mesostigma viride'', covered by an outer layer of basket‐like scales instead of a cell wall. It is the only known genus in the class Mesostig ...

tales ***** Chlorokybales ****

Klebsormidiophyceae Klebsormidiales is an order of charophyte algae. Until Bierenbroodspot et al.'s phylogeny, it was the only order in the class Klebsormidiophyceae, sister of the Phragmoplastophyta. , AlgaeBase AlgaeBase is a global species database of infor ...

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Phragmoplastophyta The Phragmoplastophyta (Lecointre & Guyader 2006) are a proposed sister clade of the Klebsormidiaceae in the Streptophyte/Charophyte clade. The Phragmoplastophyta consist of the Charophyceae and another unnamed clade which contains the Coleoch ...

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Charophyceae Charophyceae is a class of charophyte green algae. AlgaeBase places it in division Charophyta. Extant (living) species are placed in a single order Charales, commonly known as "stoneworts" and "brittleworts". Fossil members of the class may be p ...

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Coleochaetophyceae Coleochaetophyceae is a class of charophyte algae related to land plants (only Zygnematophyceae is closer). There are about 35 known species, and are predominantly found in freshwater where they live periphytic on the surface of aquatic plant ...

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Zygnematophyceae 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. The Zygnematophyceae are the sister clade of the Embryophyta (l ...

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Embryophyta The embryophytes () are a clade of plants, also known as Embryophyta (Plantae ''sensu strictissimo'') () or land plants. They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands. Embryophy ...

(land plants)

Phylogeny

In 2019, a phylogeny based on genomes and transcriptomes from 1,153 plant species was proposed. The placing of algal groups is supported by phylogenies based on genomes from the Mesostigmatophyceae and Chlorokybophyceae that have since been sequenced. Both the "chlorophyte algae" and the "streptophyte algae" are treated as paraphyletic (vertical bars beside phylogenetic tree diagram) in this analysis. The classification of Bryophyta is supported both by Puttick ''et al.'' 2018, and by phylogenies involving the hornwort genomes that have also since been sequenced. Ancestrally, the green algae were flagellates.

References

{{Taxonbar, from=Q11973077 Biological classification Subkingdoms Taxa named by Thomas Cavalier-Smith