Yellow-green algae

{{Short description|Class of algae}} {{Automatic taxobox | name = Yellow-green algae | image = Album général des Cryptogames, Pl. 20.jpg | image_caption = Examples of xanthophytes (repair the unequal flagella in the cells) | taxon = Xanthophyceae | authority = Allorge, 1930,<ref>{{cite journal | last1 = Allorge | first1 = P | year = 1930 | title = Heterocontées ou Xanthophycées? | journal = Rev. Alg. | volume = 5 | page = 230 }}</ref> emend. Fritsch, 1935<ref>Fritsch, F.E. (1935) ''The Structure and Reproduction of the Algae. Volume I. Introduction, Chlorophyceae, Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Colourless Flagellata''. Cambridge University Press, Cambridge.{{page needed|date=October 2014}}</ref> | synonyms = * Heterokontae Luther, 1899<ref>{{cite journal |last1=Lüther |first1=A. |year=1899 |title=Über Chlorosaccus eine neue Gattung der Süsswasseralgen |journal=Bihang Til Kongliga Svenska Vetenskaps-Akademiens Handlingar |volume=24 |pages=1–22 |oclc=178060545}}</ref> * Heterochloridia Pascher, 1912 * Tribophyceae Hibberd, 1981<ref>{{cite journal |first1=D. J. |last1=Hibberd |date=February 1981 |title=Notes on the taxonomy and nomenclature of the algal classes Eustigmatophyceae and Tribophyceae (synonym Xanthophyceae) |journal=Botanical Journal of the Linnean Society |volume=82 |issue=2 |pages=93–119 |doi=10.1111/j.1095-8339.1981.tb00954.x}}</ref> * Heteromonadida Leedale, 1983<ref>{{cite book |last=Leedale |first=G.F. |year=1985 |chapter=Order 5, Heteromonadida Leedale, 1983 |pages=70– |editor1-first=John J. |editor1-last=Lee |editor2-first=Seymour Herbert |editor2-last=Hutner |editor3-first=Eugene C. |editor3-last=Bovee |title=An illustrated Guide to Protozoa |publisher=Society of Protozoologists |location=Lawrence, Kansas}}{{page needed|date=October 2014}}</ref> * Xanthophyta Hibberd, 1990<ref>{{cite book |last1=Hiberd |first1=D. J. |year=1990 |chapter=Phylum Xanthophyta |editor1-first=L. |editor1-last=Margulis |editor1-link=Lynn Margulis |editor2-first=J. O. |editor2-last=Corliss |editor3-first=M. |editor3-last=Melkonian |editor4-first=D. J. |editor4-last=Chapman | display-editors = 3|title=Handbook of Protoctista |pages=686–97 |publisher=Jones and Bartlett Publishers |location=Boston, Massachusetts, USA}}</ref> }}

'''Yellow-green algae''' or the '''Xanthophyceae''' ('''xanthophytes''') are an important group of heterokont algae. Most live in fresh water, but some are found in marine and soil habitats. They vary from single-celled flagellates to simple colonial and filamentous forms. Xanthophyte chloroplasts contain the photosynthetic pigments chlorophyll ''a'', chlorophyll ''c'', β-carotene, and the carotenoid diadinoxanthin.<ref name="Stace">{{Cite book | last1 = Stace | first1 = Clive A. | author-link = Clive A. Stace |title = Plant Taxonomy and Biosystematics | publisher = Cambridge University Press |year=1991 | isbn = 978-0-521-42785-2 }}{{page needed|date=October 2014}}</ref> Unlike other Stramenopiles (heterokonts), their chloroplasts do not contain fucoxanthin, which accounts for their lighter colour. Their storage polysaccharide is chrysolaminarin.<ref name="Stace" /> Xanthophyte cell walls are produced of cellulose and hemicellulose.<ref name="Stace" /> They appear to be the closest relatives of the brown algae.

==Classifications== The species now placed in the Xanthophyceae were formerly included in the Chlorophyceae.<ref>Chapman, V. J. ''An Introduction to the Study of Algae''. University Press, Cambridge; The Macmillan Company, New York, 1941, p. 18, [https://archive.org/stream/introductiontost00chap#page/18/mode/2up].</ref> In 1899, Lüther created the group Heterokontae for green algae with unequal flagella. Pascher (1914) included the Heterokontae in the Chrysophyta. In 1930, Allorge renamed the group as Xanthophyceae.

The monadoid (unicellular flagellates) and also sometimes the amoeboid species have been included by some authors in the Protozoa or Protista,<ref>Copeland (1956), p. 63</ref><ref>{{cite journal | last1 = Fernández-Galiano | first1 = D | year = 1990 | title = Las nuevas clasificaciones de los organismos eucarióticos unicelulares. Protistología versus Protozoología | url = http://repositorio.fciencias.unam.mx:8080/xmlui/bitstream/handle/11154/143377/42VNuevasClasificaciones.pdf?sequence=1 | journal = Rev. R. Soc. Esp. Hist Nat., (Secc. Biol.) | volume = 85 | issue = 1–4| pages = 107–125 }}</ref> as order Heterochloridina (e.g., Doflein and Reichenow, 1927–1929<ref>Doflein, F. & Reichenow, E. 1927–1929. ''Lehrbuch der Protozoenkunde'', 5th ed, G. Fischer, Jena. 1262 p.</ref>), as class Xanthomonadina, with orders Heterochloridea and Rhizochloridea (e.g., Deflandre, 1956<ref>Deflandre, G. (1952). In: Grassé, P.-P. (Ed.). ''Traité de Zoologie''. Vol. 1, fasc. 1. Phylogénie. Protozoaries: Generalités, Flagellés. Masson et Cie, Paris. pp. 212, 217, 220.</ref>), as order Heterochlorida (e.g., Hall, 1953,<ref>Hall, R.P., 1953. ''Protozoology''. Prentice-Hall, New York, [https://archive.org/details/protozoology00hall],</ref> Honigberg et al., 1964<ref>{{cite journal | last1 = Honigberg | first1 = B.M. | last2 = Balamuth | first2 = W. | last3 = Bovee | first3 = E.C. | last4 = Corliss | first4 = J.O. | last5 = Gojdics | first5 = M. | last6 = Hall | first6 = R.P. | last7 = Kudo | first7 = R.R. | last8 = Levine | first8 = N.D. | last9 = Loeblich | first9 = A.R.Jr. | last10 = Weiser | first10 = J. | last11 = Wenrich | first11 = D.H. | year = 1964 | title = A revised classification of the phylum Protozoa | journal = Journal of Protozoology | volume = 11 | issue = 1| pages = 7–20 | doi=10.1111/j.1550-7408.1964.tb01715.x| pmid = 14119564 }}</ref>), as order Heteromonadida (e.g., Leedale, 1983<ref>{{cite book |last=Leedale |first=G.F. |year=1985 |chapter=Order 5, Heteromonadida Leedale, 1983 |pages=70– |editor1-first=John J. |editor1-last=Lee |editor2-first=Seymour Herbert |editor2-last=Hutner |editor3-first=Eugene C. |editor3-last=Bovee |title=An illustrated Guide to Protozoa |publisher=Society of Protozoologists |location=Lawrence, Kansas}}{{page needed|date=October 2014}}</ref>), or as subclass Heterochloridia (e.g., Puytorac et al., 1987<ref>Puytorac, P. de, Grain, J., Mignot, J.P. ''Précis de protistologie''. Lubrecht & Cramer Ltd, 1987. 581 p.</ref>). These groups are called ambiregnal protists, as names for these have been published under either or both of the ICZN and the ICN.

===AlgaeBase (2020)=== Xanthophyceae have been divided into the following five orders in some classification systems:<ref name=AlgaeBase>{{cite web |url=https://www.algaebase.org/browse/taxonomy/?id=4354 |title=Xanthophyceae |last1=Guiry |first1=M.D. |last2=Guiry |first2=G.M. |date=2020 |website=AlgaeBase |publisher=National University of Ireland, Galway |access-date=2 June 2020}}</ref>

* ''Dictyosphaeriopsis'' * ''Groenlandiella'' * ''Halosphaeropsis'' * ''Pelagocystis'' * ''Polyedrium'' * ''Pseudopleurochloris'' * ''Raphidosphaera'' * ''Sphaerochloris'' * ''Tiresias'' * Order Botrydiales Schaffner 1922 ** Family Botrydiaceae Rabenhorst 1863 e.g. ''Botrydium'' * Order Mischococcales Fritsch 1927 ** Family Botrydiopsidaceae Hibberd 1980 e.g. ''Botrydiopsis'' ** Family Botryochloridaceae Pascher 1938 e.g. ''Ilsteria'' ** Family Centritractaceae Pascher 1937 e.g. ''Centritractus'' ** Family Characiopsidaceae Pascher 1938 e.g. ''Characiopsis'', ''Chlorothecium'' ** Family Chloropediaceae Pascher 1931 e.g. ''Chloropedia'' ** Family Gloeobotrydaceae Pascher 1937 e.g. ''Gloeobotrys'' ** Family Gloeopodiaceae Pascher 1938 e.g. ''Gloeopodium'' ** Family Mischococcaceae Pascher 1912 e.g. ''Mischococcus'' ** Family Ophiocytiaceae Lemmermann 1899 e.g. ''Ophiocytium'' ** Family Pleurochloridaceae Pascher 1937 e.g. ''Meringosphaera'', ''Pleurochloris'' ** Family Trypanochloridaceae Geitler ex Pascher 1938 e.g. ''Trypanochloris'' * Order Rhizochloridales Pascher 1925 ** Family Myxochloridaceae Pascher 1937 e.g. ''Myxochloris'' ** Family Rhizochloridaceae Pascher 1925 e.g. ''Rhizochloris'' ** Family Stipitococcaceae Pascher ex Smith 1933 e.g. ''Stipitococcus'' * Order Tribonematales Pascher 1939 ** Family Heterodendraceae Pascher 1939 e.g. ''Heterodendron'' ** Family Heteropediaceae Hibberd 1982 e.g. ''Heterococcus'', ''Heteropedia'' ** Family Neonemataceae Ettl 1977 e.g. ''Neonema'' ** Family Tribonemataceae West 1904 e.g. ''Tribonema'' ** Family Xanthonemataceae Silva 1980 e.g. ''Xanthonema'' * Order Vaucheriales Nägeli ex Bohlin 1901<ref name="Christensen 87">Christensen, T. 1987. ''Seaweeds of the British Isles.'' Volume 4 Tribophyceae (Xanthophyceae). British Museum (Natural History), London {{ISBN|0-565-00980-X}}{{page needed|date=October 2014}}</ref> ** Family Vaucheriaceae (Gray) Dumortier 1822 e.g. ''Vaucheria''

===Lüther (1899)=== Classification according to Lüther (1899):<ref>{{cite journal | last1 = Lüther | first1 = A | year = 1899 | title = Über Chlorosaccus eine neue Gattung der Süsswasseralgen | journal = Bihang Til Kongliga Svenska Vetenskaps-Akademiens Handlingar | volume = 24 | pages = 1–22 }}</ref><ref>Pascher (1912), p. 9, [https://www.biodiversitylibrary.org/item/13897#page/35/mode/1up].</ref>

* Class Heterokontae ** Order Chloromonadales ** Order Confervales

===Pascher (1912)=== Classification according to Pascher (1912):<ref>{{cite journal | last1 = Pascher | first1 = A | year = 1912 | title = Zur Gliederung der Heterokonten (Kieine Beiträge zur Kenntnis unserer Mikroflora 3). | url = https://www.biodiversitylibrary.org/item/13897#page/32/mode/1up| journal = Hedwigia | volume = 53 | pages = 6–22 }}</ref>

* Heterokontae ** Heterochloridales ** Heterocapsales ** Heterococcales ** Heterotrichales ** Heterosiphonales

===Fritsch (1935)=== Fritsch (1935) recognizes the following orders in the class Xanthophyceae:<ref>Fritsch, F.E. (1935) ''The Structure and Reproduction of the Algae. Volume I. Introduction, Chlorophyceae. Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenineae, Colourless Flagellata''. Vol. I, Cambridge University Press, Cambridge, [https://books.google.com/books?id=hOa74Hm4zDIC&pg=PA26].</ref>

*Order Heterochloridales ** Family Heterochloridaceae (e.g., ''Heterochloris'') ** Family Heterocapsaceae (e.g., ''Chlorogloea'') ** Family Mischococcaceae (e.g., ''Mischococcus'') ** Family Heterorhizidaceae (e.g., ''Rhizolekane'') *Order Heterococcales ** Family Halosphaeraceae (e.g., ''Halosphaera'') ** Family Myxochloridaceae (e.g., ''Myxochloris'') ** Family Chlorobotrydaceae(e.g., ''Chlorobotrys'') ** Family Chlorotheciaceae (e.g., ''Chlorothecium'') ** Family Ophiocytiaceae (e.g., ''Ophiocytium'') *Order Heterotrichales ** Family Tribonemataceae (e.g., ''Tribonema'') ** Family Heterocloniaceae (e.g., ''Heterodendron''[?]) *Order Heterosiphonales ** Family Botrydiaceae (e.g., ''Botrydium'')

===Smith (1938)=== In the classification of Smith (1938), there are six orders in the class Xanthophyceae, placed in the division Chrysophyta:

*Order Heterochloridales (e.g., ''Chlorochromonas'') *Order Rhizochloridales (e.g., ''Chlorarachnion'') *Order Heterocapsales (e.g., ''Chlorosaccus'') *Order Heterotrichales (e.g., ''Tribonema'') *Order Heterococcales (e.g., ''Botrydiopsis'') *Order Heterosiphonales (e.g., ''Botrydium'')

===Pascher (1939)===

Pascher (1939) recognizes 6 classes in Heterokontae:<ref>Pascher, A., 1939. Heterokonten. In: ''Rabenhorsts Kryptogamen-Flora von Deutschland'', Österreich und der Schweiz. Aufl. 2 Bd. XI. Leipzig: Akad. Verlagsges (1937–1939). p. 204, [http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=1023&Pagina=215].</ref> *Class Heterochloridineae *Class Rhizochloridineae *Class Hetcrocapsineae *Class Heterococcincae *Class Hetcrotrichineae *Class Heterosiphonineae

===Copeland (1956)=== Copeland (1956) treated the group as order Vaucheriacea:<ref>Copeland, H. F. (1956). ''The Classification of Lower Organisms''. Palo Alto: Pacific Books, pp. 63–67, [https://archive.org/stream/classificationof00cope#page/62/mode/2up].</ref>

* Kingdom Protoctista ** Phylum Phaeophyta *** Class Heterokonta **** Order Vaucheriacea ***** Family Chlorosaccacea ***** Family Mischococcacea ***** Family Chlorotheciacea ***** Family Botryococcacea ***** Family Stipitococcacea ***** Family Chloramoebacea ***** Family Tribonematacea ***** Family Phyllosiphonacea

===Ettl (1978), van den Hoek et al. (1995)===

In a classification presented by van den Hoek, Mann and Jahns (1995), based on the level of organization of the thallus, there are seven orders:

* Order Chloramoebales (e.g., ''Chloromeson'') - flagellate organisms * Order Rhizochloridales (e.g., ''Rhizochloris, Myxochloris'') - ameboid organisms * Order Heterogloeales (e.g., ''Gloeochloris'') - palmelloid (tetrasporal) organisms * Order Mischococcales (e.g., ''Chloridella, Botrydiopsis, Characiopsis, Ophiocytium'') - coccoid organisms * Order Tribonematales (e.g., ''Tribonema, Heterococcus, Heterodendron'') - filamentous organization * Order Botrydiales (e.g., ''Botrydium'') - siphonous organization; sexual reproduction isogamous or anisogamous * Order Vaucheriales (e.g., ''Vaucheria'') - siphonous organization; sexual reproduction oogamous

These are the same orders of the classification of Ettl (1978),<ref>Ettl, H., 1978. Xanthophyceae. In: Ettl, H., Gerloff, J., Heynig, H. (Eds.), Süsswasserflora von Mitteleuropa, Bd. 3. 1. Teil. Gustav Fischer Verlag, Stuttgart, pp. 1–530.</ref> an updated version of the classic work by Pascher (1939). Ultrastructural and molecular studies shows that the Mischococcales might be paraphyletic, and the Tribonematales and Botrydiales polyphyletic,<ref>{{cite journal | last1 = Negrisolo | first1 = E. | display-authors = etal | year = 2004 | title = Morphological convergence characterizes the evolution of Xanthophyceae (Heterokontophyta): evidence from nuclear SSU rDNA and plastidial rbcL genes | url = https://www.researchgate.net/publication/8386968 | journal = Molecular Phylogenetics and Evolution | volume = 33 | issue = 1| pages = 156–170 | doi=10.1016/j.ympev.2004.04.016 | pmid=15324845}}</ref> and suggests two orders at most be used until the relationships within the division are sorted.<ref name="pmid16248873">{{cite journal |vauthors=Adl SM, Simpson AG, Farmer MA, etal |title=The new higher level classification of eukaryotes with emphasis on the taxonomy of protists |journal=The Journal of Eukaryotic Microbiology |volume=52 |issue=5 |pages=399–451 |year=2005 |pmid=16248873 |doi=10.1111/j.1550-7408.2005.00053.x|doi-access=free }}</ref>

===Maistro et al. (2009)=== Informal groups, according to Maistro et al. (2009):<ref>{{cite journal |vauthors=Maistro S, Broady PA, Andreoli C, Negrisolo E |title=Phylogeny and taxonomy of Xanthophyceae (Stramenopiles, Chromalveolata) |journal=Protist |volume=160 |issue=3 |pages=412–26 | date=August 2009 |pmid=19386545 |doi=10.1016/j.protis.2009.02.002}}</ref> * Botrydiopsalean clade * Chlorellidialean clade * Tribonematalean clade * Vaucherialean clade

Unicellular flagellates, amoeboid and palmelloid taxa were not included in this study.

===Adl et al. (2005, 2012)=== According to Adl et al. (2005, 2012):<ref name="pmid16248873" /><ref>{{cite journal |vauthors=Adl SM, Simpson AG, Lane CE, etal |title=The revised classification of eukaryotes |journal=The Journal of Eukaryotic Microbiology |volume=59 |issue=5 |pages=429–93 | date=September 2012 |pmid=23020233 |pmc=3483872 |doi=10.1111/j.1550-7408.2012.00644.x}}</ref> * Tribonematales (genera ''Botrydium, Bumilleriopsis, Characiopsis, Chloromeson, Heterococcus, Ophiocytium, Sphaerosorus, Tribonema, Xanthonema'') * Vaucheriales (genus ''Vaucheria'')

<gallery mode=packed heights=220> File:Stipitococcus capense.svg|''Stipitococcus capense'' (Rhizochloridales) File:British fresh-water algae, exclusive of Desmidieae and Diatomaceae (1882-1884) (20231360259).jpg|''Ophiocytium arbusculum'' (Mischococcales), formerly ''Sciadium arbuscula'' File:British fresh-water algae, exclusive of Desmidieae and Diatomaceae (1882-1884) (19795451234).jpg|''Vaucheria'' sp. File:Album général des Cryptogames, Pl. 21.jpg|Other genera </gallery>

<gallery mode=packed> File:Alger, Botydium granulatum, Nordisk familjebok.png|''Botrydium granulatum'' (Botrydiales) File:Vaucheria sp thallus 01.jpg|''Vaucheria'' sp. (Vaucheriales), thallus File:Vaucheria sp sexial reproductive organ01.jpg|''Vaucheria'' sp., sexual reproductive organs </gallery>

==See also== * Coccolithophore * Cyanobacteria * Diatom

==References== {{Wikispecies|Xanthophyceae}} {{Reflist}}

Category:Xanthophyceae