Cosmocladium

Cosmocladium
Scientific classification
Kingdom:	Plantae
Class:	Zygnematophyceae
Order:	Desmidiales
Family:	Desmidiaceae
Genus:	Cosmocladium; Brébisson, 1856
Type species
	Cosmocladium pulchellum; Brébisson
Species
	C. carinthiacum; C. constrictum; C. hitchcockii; C. perissum; C. pulchellum; C. saxonicum; C. subramosum; C. tuberculatum;

Cosmocladium is a genus of freshwater green algae, specifically of the Desmidiaceae.^[1] Currently there are 7 accepted species, though there are 11 described.^[2] The holotype is Cosmocladium pulchellum Brébisson described in 1856.^[2]

Cosmocladium is a colonial organism, consisting of usually up to 16 cells.^[2] Colonies may be free-floating or attached to filamentous algae. The cells are typically quite small, consisting of two identical halves called semicells, and are constricted at the isthmus where the semicells are joined.^[3] Cells are connected to each other by thin strands (bundles of microfibrils)^[4] secreted by special pores near isthmus, forming a branched network. Semicells are ellipsoid or elongate-oval in apical view, with one chloroplast per semicell each containing a central pyrenoid. The cell wall is smooth. A single nucleus is found in the center of each cell.^[2]

Asexual reproduction occurs by binary cellular division, similar to that of most other desmids, or by fragmentation of colonies. Sexual reproduction occurs by conjugation; the resulting zygospores are spherical with short, stout spines.^[2]

Cosmocladium is unusual among desmids in having branched, irregular colonies. It is not typically confused with other genera except for Heimansia, which differs in having cells attached to each other by remnants of the parental cell wall.^[5] Species are distinguished by cell shape.^[3]

Cosmocladium is found mainly in acidic, oligotrophic waters in North America, Europe, Asia, and New Zealand.^[2]

References

^ See the NCBI webpage on Cosmocladium. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.
^ ^a ^b ^c ^d ^e ^f Guiry, M.D.; Guiry, G.M. "Cosmocladium". AlgaeBase. University of Galway.
^ ^a ^b Prescott, G. W.; Croasdale, H. T.; Vinyard, W. C.; Bicudo, C. E. M. (1981). A Synopsis of North American Desmids. Part II: Desmidiaceae: Placodermae. Section 3. Lincoln: University of Nebraska Press. p. 720. ISBN 9780835737920.
^ Coesel, P.F.M.; Meesters, K.[J.]. Desmids of the Lowlands. 2nd revised & extended edition. Zeist: KNNV Uitgeverij. p. 424. ISBN 9789050119481.
^ 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.

External links

Guiry, M.D.; Guiry, G.M. "Cosmocladium". AlgaeBase. University of Galway.
AlgaTerra database
Index Nominum Genericorum

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[1] See the NCBI webpage on Cosmocladium. Data extracted from the "NCBI taxonomy resources". National Center for Biotechnology Information. Retrieved 2007-03-19.

[AlgaeBase-2] ^ ^a ^b ^c ^d ^e ^f Guiry, M.D.; Guiry, G.M. "Cosmocladium". AlgaeBase. University of Galway.

[Prescott1981-3] Prescott, G. W.; Croasdale, H. T.; Vinyard, W. C.; Bicudo, C. E. M. (1981). A Synopsis of North American Desmids. Part II: Desmidiaceae: Placodermae. Section 3. Lincoln: University of Nebraska Press. p. 720. ISBN 9780835737920.

[4] Coesel, P.F.M.; Meesters, K.[J.]. Desmids of the Lowlands. 2nd revised & extended edition. Zeist: KNNV Uitgeverij. p. 424. ISBN 9789050119481.

[Hall2014-5] 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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