161,670 species and infraspecific names are in the database, 22,723 images, 63,671 bibliographic items, 473,639 distributional records.

Polytretus Sauvageau, 1900

Classification:
Empire Eukaryota
Kingdom Chromista
Phylum Ochrophyta
Class Phaeophyceae
Subclass Fucophycidae
Order Ectocarpales
Family Chordariaceae

Holotype species: Polytretus reinboldii (Reinke) Sauvageau

Original publication and holotype designation: Sauvageau, C. (1901). Remarques sur les Sphacélariacées. Journal de Botanique [Morot] 15: 408-418.
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Taskin, E. & Pedersen, P.M. (2012). First report of the alien brown alga Botrytella parva (Takamatsu) H.-S. Kim (Chordariaceae, Phaeophyceae) from the eastern Mediterranean Sea. Botanica Marina 55(5): 467-471.

Taxonomic notes
Resurrection of the generic name Polytretus recommended by Taskin & Pedersen (2012: 468). - (19 Feb 2013) - Wendy Guiry

Description: The genus has a heterotrichous thallus organization; the erect filaments are branched with lateral and terminal true phaeophycean hairs. The formation and ultimate morphology of the plurilocular sporangia is the characteristic feature of this genus. What appears to be one plurilocular sporangium based on its general morphology is in fact a sorus of plurilocular sporangia. Their formation is restricted to laterals. The basal cells of the laterals undergo 1-more longitudinal divisions. Each resulting cell is a sporangium initial which subdivides and forms a sporangium with an apical opening at maturity. The sporangia are conical in outline, however, sometimes slightly constricted (reflects the original segmentation of the filament), and dentate. The growth is diffuse intercalary. Polytretus and other members of the Sorocarpaceae show sympodial branching, i.e. the first vegetative cell under the hair meristem forms a lateral which pushes the hair into a lateral position. Monopodial laterals are also formed. The chloroplasts are disc-shaped. The life history is of the direct type (Pedersen 1977, Kornmann and Sahling 1984).

Information contributed by: P. M. Pedersen. The most recent alteration to this page was made on 19 Feb 2013 by Wendy Guiry.

Numbers of names and species: There are 1 species names in the database at present.

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.

References
Taskin, E. & Pedersen, P.M. (2012). First report of the alien brown alga Botrytella parva (Takamatsu) H.-S. Kim (Chordariaceae, Phaeophyceae) from the eastern Mediterranean Sea. Botanica Marina 55(5): 467-471.

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: 28 December 2000 by M.D. Guiry

Verified by: 19 February 2013 by Wendy Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42919

Citing AlgaeBase
Please cite this record as:
Wendy Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 14 June 2021.

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