153,615 species and infraspecific names are in the database, 20,981 images, 59,407 bibliographic items, 412,628 distributional records.

Tetrastrum Chodat, 1895

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Chlorophyta infrakingdom
Phylum Chlorophyta
Subphylum Chlorophytina
Class Chlorophyceae
Order Sphaeropleales
Family Scenedesmaceae

Holotype species: Tetrastrum heteracanthum (Nordstedt) Chodat

Original publication and holotype designation: Chodat, R. (1895 '1894'). Materiaux pour servir a l'histoire des Protococcoidées. II. Bulletin de l'Herbier Boissier 3: 109-114.

Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Sphaeropleales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 280-355. Ruggell: A.R.A. Gantner Verlag K.-G..

Description: Thalli colonial, forming mostly 4-celled coenobia, 5-23 µm in one plane, these sometimes aggregated into compound colonies with 16 (rarely more) cells. Structureless mucilaginous envelope absent to present. Cells tightly joined, without or with small empty space in center of coenobium. Cells ovoid, triangular or trapezoidal, 2-11.5 µm long, with longitudinal axis in plane of coenobium. Cell walls smooth but with granulations observed with electron microscope. Species with or without spines to 46 µm long on outer face of cell; with various morphologies including one or two long spines, one short and one long spines, or 3-6 short spines. Cells uninucleate; chloroplasts 1-4 and parietal, band-shaped to discoid; pyrenoids present or absent. Asexual reproduction by autospores; 4 (occasionally 2) per sporangium and organized into coenobia; released by rupture of parental cell wall on outer face of cell. Flagellated stages and sexual reproduction unknown. Tetrastrum planktonic in freshwater, mostly in eutrophic conditions; locally common to abundant. Species distinguished based on details of cell size and shape, spine morphology and presence/absence of pyrenoids. Species with wall granulations or warts as observed with light microscope would be assigned to Pseudostaurastrum.

Information contributed by: D. Garbary and E. Hegewald. The most recent alteration to this page was made on 10 Jul 2012 by Michael Guiry.

Numbers of names and species: There are 26 species names in the database at present, as well as 13 infraspecific names. Of the species names, 13 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Click here to also show infraspecific names in the list below.

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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.

Created: 11 April 2002 by M.D. Guiry

Verified by: 10 July 2012 by Michael Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43477

Citing AlgaeBase
Please cite this record as:
Michael Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 19 November 2018.

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