About Pediastrum duplex Meyen
Pediastrum duplex Meyen is a species of freshwater green alga belonging to the genus Pediastrum, and it is the type species of this genus. This alga forms nonmotile, flat, circular coenobia (colonies) that have a fixed number of cells. Most colonies hold 8 to 32 cells, while colonies with 4, 64, or 128 cells are rare. There are small holes between the cells in a colony, and these holes have a smaller diameter than the cells themselves. The individual cells are polygonal, with a distinctly rectangular outline and concave sides. The outer cells of the coenobium each have two triangular lobes that are longer than the cell body. The tips of these lobes bear very short rosettes, which may also have fine bristles. The cell wall is most often smooth, but it can sometimes have a clear sculptured texture. Pediastrum duplex primarily reproduces asexually through the formation of autocolonies, though sexual reproduction has also been observed. It is a very common component of freshwater phytoplankton and has a cosmopolitan distribution. Because its cell walls are resistant to decay, remains of Pediastrum duplex cell walls have been recovered from Holocene lake sediments.
