Chlorogonium Ehrenberg, 1836

Holotype species: Chlorogonium euchlorum (Ehrenberg) Ehrenberg

Original publication and holotype designation: Ehrenberg, C.G. (1836). Zusätze zur Erkenntniss grosser organischer Ausbildung in den kleinsten thierischen Organismen. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin 1835: 150-181, 1 pl.

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Description: Unicellular thalli typically spindle-shaped (fusiform) or strongly elongated along flagellar axis. Each cell with more than two contractile vacuoles scattered throughout the cytoplasm. Two isokont, anterior flagella are typically shorter than the length of the cell. Single, large chloroplast is parietal, laminate or spiral. Pyrenoids present or absent, depending on the species. When more than one pyrenoid is present, they normally flank the anterior and posterior portions of the single, central nucleus. Distinct papillum absent. Eyespot prominent in most species at cell anterior embedded in chloroplast. Flagellar root system cruciate and composed of four sets of microtubule systems. Basal bodies exhibit clockwise absolute configuration. Mitosis characterized as closed spindle type, spindle collapses at telophase. Phycoplast system of microtubules develops in the plane of cytokinesis. First division typically transverse. Asexual reproduction by zoosporogenesis. Sporangium retains flagella and motility during sporulation. Although connection between basal body and flagella of the parental cell is severed during sporulation, flagella remain attached to the sporangial (parental) wall and are functional. Four to eight zoospores (rarely 2) typically produced. Daughter cells elongate in the longitudinal axis of the sporangial cell. Zoospores escape following dissolution of the sporangial wall. Aplanospores and akinetes (cysts) have been reported. Sexual reproduction isogamous to oogamous. Zygotes spherical with thick, flattened wall.

Information contributed by: M. Buchheim. The most recent alteration to this page was made on 2013-04-25 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Masjuk, N.P., Lilitska, G.G. & Kapustin, D.O. (2011). Chlamydomonadales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 157-218. Ruggell: A.R.A. Gantner Verlag K.-G..

Comments: Chlorogonium widespread in freshwater. Habitats include soil, temporary pools, and eutrophic lakes. Cell wall in zoospores of Chlorogonium elongatum of the type II lattice similar to Brachiomonas, Chloromonas, Polytoma, Carteria and some species of Chlamydomonas. Chlorogonium is a distinctive assemblage of freshwater species characterized by several unusual features including retention of motility, multiple (>2) contractile vacuoles, and transverse cell division. The similarities between Haematococcus and Chlorogonium noted by some taxonomists (e.g., Haematococcaceae sensu Ettl) are supported by recent results from analysis of molecular evidence.

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Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43372

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 25 April 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024