Euastrum
| Euastrum | ||||||||||||
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Euastrum divaricatum LUND 44x29 µm |
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| Scientific name | ||||||||||||
| Euastrum | ||||||||||||
| CG Ehrenberg ex Ralfs |
Euastrum is a genus of ornamental algae (Desmidiales) that occurspredominantly in bog waterswith over 40 species.
features
Euastrum are unicellular, uncultivated green algae . The cells are flattened, a central constriction, the sinus, divides the cell into two symmetrical halves. The outline of a half-cell is truncated pyramidal, rectangular or elliptical in plan view. The side margin is lobed wavy. The surface of the cells can also be wavy or bumpy. At the tip of the half-cells there is usually a wide to gap-shaped depression. Pores, warts and short spines can sit on the cell wall. In each half-cell there is a lobed chloroplast with one or more pyrenoids .
Asexual reproduction takes place in the manner typical of ornamental algae. Sexual reproduction takes place through conjugation: two neighboring cells release their protoplasts as gametes, which fuse to form a spherical zygote . The empty cell halves stick to the zygote.
The cells are 15 to 200 micrometers long, depending on the type.
Occurrence
Some species are cosmopolitan . Most species live in bog waters.
Systematics
The species of the genus cannot always be differentiated with certainty from the genus Cosmarium and Micrasterias ; the assignment to one of the three genera is in part arbitrary.
Some species also represented in Central Europe are:
- Euastrum ansatum
- Euastrum binale
- Euastrum crassum
- Euastrum denticulatum
- Euastrum didelta
- Euastrum divariatum
- Euastrum elegans
- Euastrum germanicum
- Euastrum humerosum
- Euastrum insigne
- Euastrum intermedium
- Euastrum oblongum
- Euastrum verrucosum
Euastrum bidentatum (52x30 µm)
supporting documents
- Karl-Heinz Linne von Berg, Michael Melkonian u. a .: The Kosmos algae guide. The most important freshwater algae under the microscope. Kosmos, Stuttgart 2004, ISBN 3-440-09719-6 , p. 122.
Individual evidence
- ↑ Euastrum on algaebase.org , accessed August 27, 2008.
- ↑ Heinz Streble , Dieter Krauter : Life in the water drop. Microflora and microfauna of freshwater. An identification book. 10th edition. Kosmos, Stuttgart 2006, ISBN 3-440-10807-4 , pp. 202, 212.
