About Pseudopediastrum boryanum (Turpin) E.Hegewald
Pseudopediastrum boryanum forms colonies called coenobia, which are made up of 4, 8, 16, 32, or 64 cells arranged in a flat, star-shaped disc. Coenobia are usually 25 to 180 micrometers wide. The inner cells of a coenobium are polygonal, typically measuring 6–20 μm in one dimension and 5.7–22.5 μm in the other. Marginal cells of the coenobium are typically 8–30 μm in one dimension and 9–21 μm wide. These marginal cells have slight to deep notches that create two projections. These projections can grow as long as the rest of the cell, and lie parallel to one another. The cell wall is reticulate, and covered in granules that sit at the corners of a triangular mesh. It is highly resistant to decay because it contains sporopollenin. Like related species, Pseudopediastrum boryanum typically reproduces asexually. It does this by forming zoospores inside the parental cell wall; the zoospores then join together to form new coenobia. Isogamous sexual reproduction does occur in this species, but it is only seen rarely.
