Uroglena
| Uroglena | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Uroglena | ||||||||||||
| Ehrenberg 1834 |
Uroglena is a genus of golden brown algae (Chrysophyceae) with only a few species that occur in freshwater.
features
The representatives form free-swimming, spherical colonies. The single cells are egg-shaped to inverted-pear-shaped. They are arranged radially around the center of the colony and have two flagella of different lengths. In young colonies, the cells meet in the center; in larger colonies, they are connected by a jelly. In the process, jelly threads pull from the center of the sphere to the individual cells. The cells have a nucleus and usually two contractile vacuoles that lie on the side. There are one or more rarely two brown plastids that have an eye spot . The size of the colonies is 20 to 1000 micrometers.
Asexual reproduction occurs through longitudinal division of the cells and through division of the colonies. It also comes to the formation of zoospores . Some representatives form asexual cysts (stomatocytes) that have a silicified cell wall. Sexual reproduction is not yet known of Uroglena .
Occurrence
Uroglena occurs primarily in more acidic, oligotrophic to mesotrophic waters in plankton .
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. 114.