Colacium
{{Short description|Genus of algae}}
{{Use dmy dates|date=September 2024}}
{{Automatic taxobox
|image = Colacium vesiculosum 166854747.jpg
|image_caption =Colacium vesiculosum, attached to a rotifer
|taxon = Colacium
|authority = Ehrenberg, 1834
| type_species = Colacium vesiculosum
| type_species_authority = Ehrenberg{{AlgaeBase genus | id=43647 | title=Colacium Ehrenberg, 1834 | access-date=2025-04-28 }}
}}
Colacium is a genus of algae belonging to the family Euglenaceae.{{cite web |title=Colacium Ehrenberg, 1834 |url=https://www.gbif.org/species/3208318 |website=www.gbif.org |access-date=17 April 2021 |language=en}} It has two phases: a motile phase and a sessile phase, where it is found attached to other freshwater organisms.{{cite journal | doi=10.1111/j.1529-8817.1973.tb04110.x | title= Observations on the euglenoid Colacium with special reference to the formation and morphology of attachment material | date=1973 | last1=Rosowski | first1=James R. | last2=Kugrens | first2=Paul | journal=Journal of Phycology | volume=9 | issue=4 | pages=370–383 | s2cid=83651870 }}
The genus has a cosmopolitan distribution.
Description
Colacium is a single-celled or colonial organisms. Cells are small, about 20–40 μm, and are similar to that of Euglena, and are metabolic with parietal, lobed chloroplasts each with a pyrenoid, and monomorphic, small paramylon grains. In its typical sessile phase, the cells are attached to a substrate via a mucilaginous stalk or short pillow. Cells divide to form colonies where the cells are attached by branched, dendroidal stalks.{{cite book |editor-first1=John D.|editor-last1=Wehr|editor-first2=Robert G.|editor-last2=Sheath|editor-first3=J. Patrick|editor-last3=Kociolek |date= 2014 |edition=2 |title= Freshwater Algae of North America: Ecology and Classification |last1= Triemer|first1=Richard E. |last2= Zakryś |first2=Bożena |chapter= Chapter 10. Photosynthetic Euglenoids |url= |location= |publisher= Elsevier Inc. |page= |isbn=978-0-12-385876-4 }}
Cells of Colacium can grow a flagella and become motile, escaping from the colony as a free-swimming cell.
- Colacium arbuscula {{small|Stein, 1878}}
- Colacium mucronatum {{small|Bourr. & Chadef.}}
- Colacium sideropus {{small|Skuja}}
- Colacium simplex {{small|Hub.-Pest.}}
- Colacium steinii {{small|Kent}}
- Colacium vesiculosum {{small|Ehrenberg, 1838}}
References
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