Xanthidium is a genus of green algae, specifically of the Desmidiaceae.[1]
Description
Xanthidium exists as symmetrical single cells. Cells are deeply constricted, forming two halves called semicells; they are rectangular, rounded, or polygonal in front view, flattened. The angles are usually drawn out into spines, which are typically paired and sometimes branched. Semicells often have a protuberance or additional spine in the center of the semicell. Cells have two or many axile chloroplasts which fill the cell.[2][3] A notable exception is the species Xanthidium tumidum, formerly placed in the genus Staurastrum as Staurastrum tumidum. Morphologically it is triangular in cross section (unlike other species, which are flattened in cross section). Its placement in this genus is due to molecular data.[4]
Identification
Species identification of Xanthidium depends on the shape of the cell, cell wall ornamentation, and location and number of the spines. However, some species such as Xanthidium antilopaeum are notoriously polymorphic.[5]
Habitat
Like other desmids, most species of Xanthidium prefer acidic waters.[6]
References
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^ See the NCBI webpage on Xanthidium. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
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^ Guiry, M.D.; Guiry, G.M. "Xanthidium". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2023-04-29.
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^ Hall, John D.; McCourt, Richard M. (2014). "Chapter 9. Conjugating Green Algae Including Desmids". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. ISBN 978-0-12-385876-4.
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^ Stastny, Jan; Skaloud, Pavel; Langenbach, Dorothee; Nemjova, Katarina; Neustupa, Jiri (2013). "Polyphasic evaluation of Xanthidium antilopaeum and Xanthidium cristatum (Zygnematophyceae, Streptophyta) species complex". Journal of Phycology. 49 (2): 401–416. doi:10.1111/jpy.12051. PMID 27008526. S2CID 23597409.
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^ Matthews, Robin A. (2023). "Freshwater Algae in Northwest Washington, Volume III. Desmids, Part A". A Collection of Open Access Books and Monographs. Western Washington University.
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^ Prescott, G. W.; Bicudo, C. E. M.; Vinyard, W. C. (1982). A Synopsis of North American Desmids. Part II: Desmidiaceae: Placodermae. Section 4. Lincoln: University of Nebraska Press. p. 700.
