Sirogonium Kützing, 1843, nom. cons.
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.
Request PDFDescription: 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 2022-09-26 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as neuter.
Most recent taxonomic treatment adopted: Hess, S., Williams, S.K., Busch, A., Irisarri, I., Delwiche, C.F., de Vries, S., Darienko, T., Roger, A.J., Archibald, J.M., Buschmann, H., von Schwartzenberg, K. & de Vries, J. (2022). A phylogenomically informed five-order system for the closest relatives of land plants. Current Biology 32: 1-10.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43563
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 September 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
