Desmidiales


Desmidiales

 

an order of green algae of the subphylum Conjugatophytina. There are 25 genera comprising 2,000 species. The Desmidiales are microscopic unicellular free-living or occasionally filamentous forms. The cells consist of two symmetrical halves with a single nucleus in the center. Each half of the cell contains a discoid chromatophore. Reproduction takes place by division into two cells on the transverse plane; the sexual process is conjugation. The zygote germinates after a period of dormancy, usually producing two new individuals. The Desmidiales live in fresh water, usually in peat marshes and in bodies of water with little lime; certain varieties are found in soil.

REFERENCE

Kosinskaia, E. K. Desmidievye vodorosli, fascicle 1. Moscow-Leningrad, 1960. (Flora sporovykh rastenii SSSR, vol. 5.)