Tetrastrum Chodat, 1895

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.

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 2012-07-10 by Michael Guiry.

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

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..

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=43477

Citing AlgaeBase
Cite this record as:
Michael Guiry in Guiry, M.D. & Guiry, G.M. 10 July 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 28 November 2022

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