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

Sirogonium Kützing, 1843, nom. cons.

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Streptophyta infrakingdom
Phylum Charophyta
Class Conjugatophyceae (Zygnematophyceae)
Order Zygnematales
Family Zygnemataceae

Holotype species: Sirogonium sticticum (Smith) Kützing

Original publication and holotype designation: Kützing, F.T. (1843). Phycologia generalis oder Anatomie, Physiologie und Systemkunde der Tange. Mit 80 farbig gedruckten Tafeln, gezeichnet und gravirt vom Verfasser. pp. [part 1]: [i]-xxxii, [1]-142, [part 2:] 143-458, 1, err.], pls 1-80. Leipzig: F.A. Brockhaus.
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Taxonomic status: currently recognized as a distinct genus.

Gender: This genus name is currently treated as neuter.

Most recent taxonomic treatment adopted: Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.

Description: Thalli comprised of unbranched uniseriate filaments intertwinded to form extensive skeins. Cells cyslindrical, from 32-115 µm diamter, up to several times as long; cell wall two-layered with inner cellulose, outer mucilage layer; end walls plane; no flagellated stages. Cells uninucleate; chloroplasts 2 to 10 per cell, ribbonlike with pyrenoids. Filaments similar vegetatively to Spirogyra, except ribbonlike chloroplasts straighter instead of coiled. Also unlike Spirogyra, Sirogonium lacks outer mucilage layer and is markedly nonslimy to the touch. Nucleus central in cell, suspended by cytoplasmic strands. Chromosomes range in size from dotlike (<1.5 µm) to rodlike (>4 µm). Haploid chromosome number 6 to 100; varies inversely with chromosome size. Nucleolar organizing chromosomes with satellites often conspicuous at anaphase. Akinetes common. Life cycle haplobiontic, meiosis zygotic. Sexual reproduction by scalariform conjugation as in Spirogyra; conjugation tubes usually absent. Gametangia from different filaments adhere; gametes anisogamous; female gametangium and gamete slightly larger; smaller male gamete motile without flagella. Fertile cells intermittent along filament; single cells or pairs of adjacent cells in a filament may become fertile; gametangium divides to produce two daughter cells, smaller of which produces gamete or parthenospore; one filament commonly conjugates with many others, thus conjugating mass is a tangled net of adhering filaments. Zygospores most often ellipsoid, but some ovoid or spherical. Filaments usually found as free-floating masses. Occurs in freshwater habitats on all continents (unreported for Antarctica), but rare compared to Spirogyra, Mougeotia, or Zygnema. Experimental work mostly on life cycles and nuclear cytology. No economic use or nuisance. Like other Zygnematales, Sirogonium a member of Charophyceae and thus related to lower land plants. Morphology and chloroplast DNA studies indicate close relationship to Spirogyra.

Information contributed by: R.M. McCourt and R.W. Howshaw. The most recent alteration to this page was made on 19 Oct 2015 by M.D. Guiry.

Numbers of names and species: There are 27 species names in the database at present, as well as 12 infraspecific names. Of the species names, 24 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.

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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: 19 October 2015 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43563

Citing AlgaeBase
Please cite this record as:
M.D. 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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