Pediastrum Meyen
From Greek pedion, "plain" + astron, "star"
Pediastrum is a common, nonmotile green alga with flattened colonies of cells in an elaborate starlike pattern. Pediastrum colonies are coenobial - the number and arrangement of cells is genetically determined for each species. The colonies are made up of at least four cells. The cells are often notched or lobed, and sometimes bear short horns or bristles that both improve buoyancy in the water column and help to prevent predation. The cell walls may be smooth or ornamented. The parietal chloroplasts have a single pyrenoid.