Sirogonium Kützing, 1843: 278
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, -142, [part 2:] 143-458, 1, err.], pls 1-80. Leipzig: F.A. Brockhaus.
Taxonomic status: currently recognized as a distinct genus.
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.
NCBI Nucleotide Sequences
Numbers of names and species: There are 29 species (and infraspecific) names in the database at present, of which 23 have been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently 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):
Sirogonium calosporum Zhu C
Sirogonium ceylanicum Wittrock C
Sirogonium decoratum Prescott C
Sirogonium denticulatum Zhu C
Sirogonium floridanum (Transeau) G.M.Smith C
Sirogonium fuscosporum Woodhead & Tweed C
Sirogonium fuscosporum Woodhead & Tweed C
Sirogonium guangzhouense Zhu C
Sirogonium hui (L.C.Li) Transeau C
Sirogonium illinoisense (Transeau) G.M.Smith C
Sirogonium indicum Singh C
Sirogonium inflatum Dixit C
Sirogonium kamatii Kadlubowska C
Sirogonium khoriense Masud-ul-Hassan & M.Nizamuddin C
Sirogonium megasporum (C.-C.Jao) Transeau S
Sirogonium melanosporum (Randhawa) Transeau C
Sirogonium phacosporum Skuja C
Sirogonium princeps Kützing S
Sirogonium pseudofloridanum (Prescott) Transeau C
Sirogonium reticulatum Randhawa C
Sirogonium retroversum H.C.Wood C
Sirogonium sticticum (Smith) Kützing C - type
Sirogonium sticticum var. loscosianum Lázaro U
Sirogonium sticticum f. tenuius (Transeau) L.A.Rundina S
Sirogonium stictum var. megasporum C.-C.Jao S
Sirogonium tenuius (Nordsted) Transeau C
Sirogonium vandalurense Iyengar C
Sirogonium ventersicum Transeau C
Sirogonium ventersicum var. melanosporum Randhawa S
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: http://www.algaebase.org/search/genus/detail/?genus_id=43563
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 12 December 2013.
Algaebase taxon LSID: urn:lsid:algaebase.org:taxname:6836