Yellow-green algae facts for kids

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Quick facts for kids Yellow-green algae

Examples of xanthophytes (repair the unequal flagella in the cells)
Scientific classification
Clade:	SAR
Phylum:	Ochrophyta
Class:	Xanthophyceae Allorge, 1930, emend. Fritsch, 1935
Synonyms
Heterokontae Luther, 1899 Heterochloridia Pascher, 1912 Tribophyceae Hibberd, 1981 Heteromonadida Leedale, 1983 Xanthophyta Hibberd, 1990

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. Unlike other heterokonts, their chloroplasts do not contain fucoxanthin, which accounts for their lighter colour. Their storage polysaccharide is chrysolaminarin. Xanthophyte cell walls are produced of cellulose and hemicellulose. They appear to be the closest relatives of the brown algae.

Classifications
See also

Classifications

The species now placed in the Xanthophyceae were formerly included in the Chlorophyceae. 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, as order Heterochloridina (e.g., Doflein and Reichenow, 1927-1929), as class Xanthomonadina, with orders Heterochloridea and Rhizochloridea (e.g., Deflandre, 1956), as order Heterochlorida (e.g., Hall, 1953, Honigberg et al., 1964), as order Heteromonadida (e.g., Leedale, 1983), or as subclass Heterochloridia (e.g., Puytorac et al., 1987). 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:

Dictyosphaeriopsis
Groenlandiella
Halosphaeropsis
Pelagocystis
Polyedrium
Pseudopleurochloris
Raphidosphaera
Sphaerochloris
Tiresias
Order Botrydiales Schaffner 1922
- Family Botrydiaceae Rabenhorst 1863
  - Asterosiphon
  - Botrydium
  - Polychloris
Order Mischococcales Fritsch 1927
- Family Botrydiopsidaceae Hibberd 1980
  - Botrydiopsis
  - Excentrochloris
  - Perone
- Family Botryochloridaceae Pascher 1938
  - Botryochloris
  - Chlorellidiopsis
  - Chlorellidium
  - Ducellieria
  - Heterodesmus
  - Ilsteria
  - Raphidiella
  - Sphaerosorus
  - Tetraktis
- Family Centritractaceae Pascher 1937
  - Bumilleriopsis
  - Centritractus
  - Pseudotetraëdron
- Family Characiopsidaceae Pascher 1938
  - Characiopsis
  - Chlorokoryne
  - Chlorothecium
  - Chytridiochloris
  - Dioxys
  - Harpochytrium
  - Hemisphaerella
  - Lutherella
  - Peroniella
- Family Chloropediaceae Pascher 1931
  - Chloropedia
- Family Gloeobotrydaceae Pascher 1937
  - Chlorosaccus
  - Asterogloea
  - Dictyosphaeriopsis
  - Gaumiella
  - Gloeobotrys
  - Gloeoskene
  - Gloeosphaeridium
  - Merismogloea
- Family Gloeopodiaceae Pascher 1938
  - Gloeopodium
- Family Mischococcaceae Pascher 1912
  - Mischococcus
- Family Ophiocytiaceae Lemmermann 1899
  - Ophiocytium
- Family Pleurochloridaceae Pascher 1937
  - Acanthochloris
  - Actinellipsoidion
  - Arachnochloris
  - Aulakochloris
  - Bracchiogonium
  - Chlorallanthus
  - Chlorapion
  - Chlorarkys
  - Chloridella
  - Chlorocloster
  - Chlorogibba
  - Diachros
  - Endochloridion
  - Isthmochloron
  - Keriosphaera
  - Meringosphaera
  - Monallanthus
  - Monodus
  - Nephrodiella
  - Osterhoutia
  - Pleurochloridella
  - Pleurochloris
  - Pleurogaster
  - Polyedriella
  - Polygoniochloris
  - Prismatella
  - Pseudogoniochloris
  - Pseudopolyedriopsis
  - Rhomboidella
  - Schilleriella
  - Skiadosphaera
  - Sklerochlamys
  - Tetraplektron
  - Trachychloron
- Family Trypanochloridaceae Geitler ex Pascher 1938
  - Trypanochloris
Order Rhizochloridales Pascher 1925
- - Garciamyxa
  - Herreramyxa
  - Requejomyxa
- Family Myxochloridaceae Pascher 1937
  - Myxochloris
- Family Rhizochloridaceae Pascher 1925
  - Aldavemyxa
  - Heterocalycina
  - Rhizochloris
- Family Stipitococcaceae Pascher ex Smith 1933
  - Rhizolekane
  - Stipitococcus
  - Stipitoporos
Order Tribonematales Pascher 1939
- Family Heterodendraceae Pascher 1939
  - Heterodendron
- Family Heteropediaceae Hibberd 1982
  - Capitulariella
  - Chaetopedia
  - Heterococcus
  - Heteropedia
  - Sphagnoikos
- Family Neonemataceae Ettl 1977
  - Neonema
- Family Tribonemataceae West 1904
  - Brachynematella
  - Bumilleria
  - Tribonema
- Family Xanthonemataceae Silva 1980
  - ?Hormotheca
  - Heterotrichella
  - Xanthonema
Order Vaucheriales Nägeli ex Bohlin 1901
- Family Vaucheriaceae (Gray) Dumortier 1822
  - Pseudodichotomosiphon
  - Vaucheria
  - Vaucheriella

Lüther (1899)

Classification according to Lüther (1899):

Class Heterokontae
- Order Chloromonadales
- Order Confervales

Pascher (1912)

Classification according to Pascher (1912):

Heterokontae
- Heterochloridales
- Heterocapsales
- Heterococcales
- Heterotrichales
- Heterosiphonales

Fritsch (1935)

Fritsch (1935) recognizes the following orders in the class Xanthophyceae:

Order Heterochloridales
- Suborder Heterochlorineae
  - Family Heterochloridaceae (e.g., Heterochloris)
- Suborder Heterocapsineae
  - Family Heterocapsaceae (e.g., Chlorogloea)
- Suborder Heterodendrineae
  - Family Mischococcaceae (e.g., Mischococcus)
- Suborder Heterorhizidineae
  - 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:

Class Heterochloridineae
Class Rhizochloridineae
Class Hetcrocapsineae
Class Heterococcincae
Class Hetcrotrichineae
Class Heterosiphonineae

Copeland (1956)

Copeland (1956) treated the group as order Vaucheriacea:

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 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), 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, and suggests two orders at most be used until the relationships within the division are sorted.

Maistro et al. (2009)

Informal groups, according to Maistro et al. (2009):

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):

Tribonematales (genera Botrydium, Bumilleriopsis, Characiopsis, Chloromeson, Heterococcus, Ophiocytium, Sphaerosorus, Tribonema, Xanthonema)
Vaucheriales (genus Vaucheria)