Conjugatophytina

a subphylum of green algae. Conjugatophytina do not form zoospores, and unicellular representatives of Conjugatophytina lack flagella. The sexual process, conjugation, occurs as a result of the fusion of the contents of two externally similar vegetative cells. Asexual reproduction is accomplished by cell division (in unicellular forms) and breaking of a filament into parts.

Conjugatophytina consists of two classes: Saccodermophyceae (the wall of the cells is in a single piece) and Placodermophyceae (the cell wall has two or several parts). Saccodermophyceae includes the orders Mezotaeniales and Gonatozygales (represented by unicellular and colonial organisms) as well as the order Zygnematales, which is represented by unbranched filamentous algae with chromatophores in the form of spiral ribbons (Spirogyra), one or two flat plates (Mougeotia), or two little stars (Zygnema). Placodermophyceae includes one order—Desmidiales. Conjugatophytina are found in fresh waters. Zygnematales often form a “scum” that floats on the surface of the water or is immersed.