Sirocladium Randhawa, 1941
Holotype species: Sirocladium kumaoense Randhawa
Original publication and holotype designation: Randhawa, M.S. (1941). Sirocladium a new terrestrial member of the Zygnemales. Botanical Gazette 103: 192-197.
Taxonomic status: currently recognized as a distinct genus.
Description: Thalli comprised on unbranched uniseriate filaments intertwined to form skeins. Rhizoids extend into the substratum from basal and intercalary vegetative cells. Cells cylindrical and curved, 28.5-64 µm in diameter, up to several times as long; cell wall two-layered with inner cellulosic, outer mucilaginous layer; end walls plane; no flagellated stages. Nucleus single per cell, held in cytoplasmic bridge between flat faces of chloroplasts. Chloroplasts two per cell; plate-like with row of pyrenoids. Asexual reproduction by aplanospores and parthenospores. Life cycle haplobiontic, meiosis zygotic. Sexual reproduction by scalariform conjugation; anisogamous with one or two sterile cells associated with gametangium. Filaments bend toward each other, gametangia adhere, and pectic ring surrounds zone of contact; no conjugation tube forms. Median wall of zygospore smooth, punctate, or with ridges.
Information contributed by: R.M. McCourt, R.W. Hoshaw & M.D. Guiry. The most recent alteration to this page was made on 14 Nov 2012 by M.D. Guiry.
Comments: Sirocladium species are known only from India, the Himalayas and Cuba in freshwater and terrestrial habitats. Trait of conjugation places Sirocladium in Zygnematales, but otherwise its phylogenetic position is unclear. Vegetative morphology is similar to Mougeotia; reproductive processes are similar to those of Sirogonium.
Numbers of names and species: There are 8 species names in the database at present, of which 8 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):
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Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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 September 2004 by Robert Wilkes
Verified by: 14 November 2012 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=47486
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 February 2020.