{{Short description|Genus of algae}} {{Automatic taxobox | image = Desmatractum bipyramidatum as Bernardinella bipyramidata.jpg | image_caption = ''Desmatractum bipyramidatum'' | taxon = Desmatractum | authority = West & G.S.West, 1902<ref name=AB_g44249/> | synonyms = ''Bernardinella'' {{small|Choda, 1925}}<br/>''Peniococcus'' {{small|Wołoszyńska, 1914}} | synonyms_ref = <ref>P. Chodat. Algue de la région du Grand St Bernard. Bulletin de la Société botanique de Genève, 1918, ''Bernardinella'' page 300 : [https://www.biodiversitylibrary.org/page/32018128#page/1022/ read on line]</ref><ref>''Peniococcus'' Woloszynska, 1914-AlgaeBase : [https://www.algaebase.org/search/genus/detail/?genus_id=50192 read on line]</ref> | type_species = ''Desmatractum plicatum'' | type_species_authority = West & G.S.West<ref name=AB_g44249/> | subdivision_ranks = Species | subdivision_ref = <ref name=AB_g44249/> | subdivision = {{Linked species list |Desmatractum bipyramidatum|(Chodat) Pascher |Desmatractum delicatissimum|Korshikov |Desmatractum elongatum|Pascher |Desmatractum indutum|(Geitler) Pascher |Desmatractum nyanzae|(Woloszynska) G.S.West ex Printz |Desmatractum obtusum|Pascher |Desmatractum plicatum|West & G.S.West |Desmatractum spryii|Nicholls }} }}
'''''Desmatractum''''' is a genus of green algae, in the order Chlamydomonadales.<ref name=AB_g44249>{{AlgaeBase genus|name=Desmatractum|id=44249|access-date=2022-02-25}}</ref> It is found in freshwater habitats such as ponds, ditches, and bogs as plankton or metaphyton.<ref name=Shubert2014>{{cite book |editor-first1=John D.|editor-last1=Wehr|editor-first2=Robert G.|editor-last2=Sheath|editor-first3=J. Patrick|editor-last3=Kociolek |date= 2014 |edition=2 |title= Freshwater Algae of North America: Ecology and Classification |last1= Shubert|first1=Elliot| last2=Gärtner |first2=Georg |chapter= Chapter 7. Nonmotile Coccoid and Colonial Green Algae |url= |location= |publisher= Elsevier Inc. |page= |isbn=978-0-12-385876-4 }}</ref> The genus is cosmopolitan, but some species are very rare.<ref name=AB_g44249/>
==Description== ''Desmatractum'' is microscopic and consists of single cells. The cells are spherical or ellipsoidal, and are surrounded by a cell envelope that tapers at both ends, making the form overall spindle-shaped. The envelope has 4 to 20 longitudinal ridges, and may be constricted at the equator. The chloroplast is parietally located and contains one or two pyrenoid.<ref name=Shubert2014/><ref name=AB_g44249/>
Species are distinguished from each other by the overall shape and size of the cells, as well as the degree of longitudinal ribbing of the cell envelopes.<ref name=AB_g44249/> Species that appear similar in the light microscope have very different ultrastructures, and this may be a sign that taxonomic revision is necessary.<ref name=AB_g44249/>
Reproduction occurs asexually, where the protoplast divides into four zoospores which are then released through a tear in the cell envelope. Zoospores are oval or elongate, with a single chloroplast and eyespot, as well as two identical anterior flagella. Sexual reproduction has not been observed in ''Desmatractum''.<ref name=AB_g44249/>
==References== {{Reflist|1}}
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Category:Chlamydomonadales genera Category:Chlamydomonadales Category:Freshwater algae
{{Chlorophyceae-stub}}