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.

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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 2012-11-14 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

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.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=47486

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 14 November 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 20 April 2024