Xanthidium Explained

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] 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.^[3]

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.^[4]

Habitat

Like other desmids, most species of Xanthidium prefer acidic waters.^[5]

External links

• • AlgaTerra database
• Index Nominum Genericorum

Notes and References

1. See the NCBI webpage on Xanthidium. Data extracted from the Web site: NCBI taxonomy resources . . 2007-03-19.
2. Book: John D.. Wehr. Robert G.. Sheath. J. Patrick. Kociolek . 2014 . 2 . Freshwater Algae of North America: Ecology and Classification . Hall. John D.. McCourt . Richard M. . Chapter 9. Conjugating Green Algae Including Desmids . Elsevier Inc. . 978-0-12-385876-4 .
3. 10.1111/jpy.12051 . Polyphasic evaluation of Xanthidium antilopaeum and Xanthidium cristatum (Zygnematophyceae, Streptophyta) species complex . 2013 . Stastny . Jan . Skaloud . Pavel . Langenbach . Dorothee . Nemjova . Katarina . Neustupa . Jiri . Journal of Phycology . 49 . 2 . 401–416 . 27008526 . 23597409 .
4. Web site: 2023 . Matthews . Robin A. . Freshwater Algae in Northwest Washington, Volume III. Desmids, Part A . A Collection of Open Access Books and Monographs . Western Washington University .
5. Book: A Synopsis of North American Desmids. Part II: Desmidiaceae: Placodermae. Section 4 . Prescott . G. W. . Bicudo . C. E. M. . Vinyard . W. C. . University of Nebraska Press . Lincoln . 1982 . 700 .