For example, a colony may include several to many cells adhering to each other as a sphere, flat sheet, or other three-dimensional shape. The cells may be embedded in a common matrix of gelatin secreted from the cells or attached by thin strands of cytoplasm. All the cells of a colony are similar in structure and function and metabolically independent. Multicellular organization is not typical of protists but describes algae of more complex design than simple colonies. Multicellular species have cells of different kinds and functions and show significant interdependence.
Green algae are the most diverse and familiar algae in freshwater.
However, a few genera live in saltwater.