Pediastrum duplex

Pediastrum is a genus of colony-forming green algae from the class of Chlorophyceae.


The representatives form flat, round and disc-shaped colonies. These consist of 4-128 cells. The diameter of the colony of up to 450 microns. The cells have a single nucleus and a single chloroplast with a pyrenoid. The shape of the cells is polygonal with concave or convex sides. The border cells, in contrast to those at the center of outwardly directed projections.

Asexual reproduction occurs by the formation of 2n zweigeißeligen zoospores per cell. This left the mother cell in a bubble forming inside this bubble, a daughter colony. Sexual reproduction takes place by isogamy. Cells of the colony forming biflagellate gametes fuse into a Hypnozygote. From this arise after meiosis moving meiospores. The meiospores transform into polyhedral, immobile cells. In these arise zoospores, leaving the sporangium as in the asexual reproduction in a bubble.


Pediastrum is found in the plankton of freshwater. You can form water blooms. It also occurs in the nursery of eutrophic standing waters. It occurs throughout the year.


The genus Pediastrum includes a few species. AlgaeBase lists 13 recognized species.


  • Pediastrum boryanum
  • Pediastrum duplex


  • K.-H. Linne von Berg, K. Hoef -Emden, B. Marin, M. Melkonian: The Cosmos algae leader. The main freshwater algae under the microscope. Kosmos, Stuttgart 2004, pp. 196, ISBN 3-440-09719-6