Viridiplantae (literally "green plants")
are a
clade of
eukaryotic
Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, 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 ...
organisms that comprise approximately 450,000–500,000 species and play important roles in both terrestrial and aquatic ecosystems. They are made up of the
green algae, which are primarily aquatic, and the land plants (
embryophytes), which emerged from within them.
Green algae traditionally excludes the land plants, rendering them a
paraphyletic group. However it is accurate to think of land plants as a kind of algae.
Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them.
They have cells with
cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell w ...
in their cell walls, and primary chloroplasts derived from
endosymbiosis
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship.
(The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within ...
with
cyanobacteria that contain
chlorophylls a and
b and lack
phycobilins.
In some classification systems, the group has been treated as a
kingdom
Kingdom commonly refers to:
* A monarchy ruled by a king or queen
* Kingdom (biology), a category in biological taxonomy
Kingdom may also refer to:
Arts and media Television
* ''Kingdom'' (British TV series), a 2007 British television drama s ...
,
under various names, e.g. Viridiplantae, Chlorobionta, or simply
Plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
ae, the latter expanding the traditional
plant kingdom to include the
green algae. 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 with green
chlorophyll. They rejected the name Viridiplantae on the grounds that some of the species are not plants, as understood traditionally.
The Viridiplantae are made up of two clades:
Chlorophyta
Chlorophyta or Prasinophyta is a taxon of green algae 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 ...
and
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 ...
as well as the basal
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 then places the order within its circumscription of Charophyta. A clade co ...
and
Chlorokybophyceae
''Chlorokybus'' is a multicellular (sarcinoid) genus of basal green algae or Charophyta, charophyte, a soil algae, alga. It has been classified as the sole member of the family Chlorokybaceae, which is the sole member of the order Chlorokybales, ...
.
Together with
Rhodophyta and
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, Viridiplantae are thought to belong to a larger clade called
Archaeplastida
The Archaeplastida (or kingdom Plantae '' sensu lato'' "in a broad sense"; pronounced /ɑːrkɪ'plastɪdə/) are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor gr ...
or Primoplantae.
A taxonomic evaluation of
eukaryotes based on
myosin distribution showed the Viridiplantae lost class-I myosins.
Phylogeny and classification
Simplified phylogeny of the Viridiplantae, according to Leliaert ''et al''. 2012.
* Viridiplantae
**
Chlorophyta
Chlorophyta or Prasinophyta is a taxon of green algae 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 ...
***core chlorophytes
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Ulvophyceae
The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data.Graham LE, Graham JM, Wilcox LW (2009) ''Algae''. 2nd Edition. Benjamin Cumming ...
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Cladophorales
Cladophorales are an order of green algae, in the class Ulvophyceae
The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data.Graham L ...
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Dasycladales
Dasycladales is an 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 live on substrates ...
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Bryopsidales
Bryopsidales is an order of green algae, in the class Ulvophyceae.
Characteristics
The thallus is filamentous and much branched and may be packed into a mass. It is coenocytic, having multi-nucleate cells consisting of cytoplasm contained withi ...
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Trentepohliales
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Ulvales
Ulvales is an order of green alga
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 e ...
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Ulotrichales
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Oltmannsiellopsidales
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Chlorophyceae
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Oedogoniales
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Chaetophorales
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Chaetopeltidales
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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 or ...
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Sphaeropleales
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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 more genetic studies at higher levels within the group.
Genera without interve ...
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Chlorellales
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Oocystaceae
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Microthamniales
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Trebouxiales
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Prasiola
''Prasiola'' is a genus of fresh water and marine green algae. Each individual plant is small but they usually grow side by side to form a green turf on rock surfaces. The genus has a cosmopolitan distribution.
Occurrence
Freshwater species ...
'' clade
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Chlorodendrophyceae
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Chlorodendrales
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Pedinophyceae
***
prasinophytes (paraphyletic)
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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 '' Amphoraemon ...
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Mamiellophyceae
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Pycnococcaceae
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Nephroselmidophyceae
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Prasinococcales
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Palmophyllales
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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 (paraphyletic assemblage of freshwater algae).
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Klebsormidiophyceae
Klebsormidiales is an order of charophyte algae. It is the only order in the class Klebsormidiophyceae, sister of the Phragmoplastophyta. , AlgaeBase
AlgaeBase is a global species database of information on all groups of algae, both marine an ...
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Phragmoplastophyta
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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 then places the order within its circumscription of Charophyta. A clade co ...
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Chlorokybophyceae
''Chlorokybus'' is a multicellular (sarcinoid) genus of basal green algae or Charophyta, charophyte, a soil algae, alga. It has been classified as the sole member of the family Chlorokybaceae, which is the sole member of the order Chlorokybales, ...
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Charophyceae
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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. It contains five orders: the Spirogloeales, the Serritaeniales ...
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Coleochaetophyceae
Coleochaetophyceae are a class of charophyte algae that includes some of the closest multicellular relatives of land plants
The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embr ...
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Embryophyta
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 siste ...
(land plants)
Cladogram
Below is a consensus reconstruction of green algal relationships, mainly based on molecular data.
Ancestrally, the green algae were flagellates.
References
{{Taxonbar, from=Q11973077
Biological classification
Subkingdoms
Taxa named by Thomas Cavalier-Smith