Micrasterias

from Wikipedia, the free encyclopedia
Micrasterias
Micrasterias furcata RALFS 1848

Micrasterias furcata RALFS 1848

Systematics
without rank: Chloroplastida
without rank: Charophyta
Class : Ornamental algae (Zygnemophyceae)
Order : Ornamental algae (Desmidiales)
Family : Desmidiaceae
Genre : Micrasterias
Scientific name
Micrasterias
C. Agardh

Micrasterias is a genus of ornamental algae (Desmidiales) that occursexclusively in freshwaterand has around 40 species. It was from the section Phykologie the German Botanical Society for the algae of the year chosen of 2008.

features

Micrasterias are unicellular, uncultivated green algae. The cells are large and flattened, and when viewed from the side they appear spindle-shaped. A central constriction, the sinus, divides the cells into two symmetrical halves. The half-cells are further divided by incisions, initially into a parietal and two lateral lobes. The lateral lobes are further subdivided into second to fourth order lobes. The cells therefore appear star-shaped. Spike-shaped cell wall processes often sit on the lobes.

The cell nucleus is colorless and lies in the bridge (isthmus) between the two halves. Each half-cell has a large, flat chloroplast with a number of pyrenoids . The shape of the chloroplast corresponds to the bulges of the lobes.

Asexual reproduction occurs through the division into two parts that are typical for ornamental algae . Sexual reproduction occurs through conjugation. The zygotes are spherical, egg-shaped or polyhedral and remain connected to the empty cell halves.

The cell size ranges from 60 to 300 µm.

Generalization with Maltese cross algae

The algae genus Micrasterias is often translated into German as Maltese cross alga. In fact, only Micrasterias crux melitensis can be called Maltese cross algae. None of the other genres.

Occurrence

The genus occurs only in fresh water, in oligotrophic, stagnant waters and in raised bogs .

Representative

  • Micrasterias truncata

  • Micrasterias sp

For example:

  • Micrasterias pinnatifida
  • Micrasterias truncata
  • Micrasterias americana
  • Micrasterias crux melitensis
  • Micrasterias furcata
  • Micrasterias apiculata
  • Micrasterias fimbriata
  • Micrasterias rotata
  • Micrasterias denticulata

supporting documents

  1. ^ Karl-Heinz Linne von Berg, Michael Melkonian: Der Kosmos-Algenführer . Ed .: Kosmos Verlag. Kosmos, ISBN 3-440-09719-6 , pp. 124 .
  2. ^ A b Heinz Streble, Dieter Krauter: Life in the water drop . In: Kosmos Verlag (Hrsg.): Kosmos Naturführer . 13th edition. Kosmos, ISBN 978-3-440-15694-0 , pp. 174 .

Web links

Commons : Micrasterias  - collection of images, videos and audio files