Nonmotile unicellular and colonial green algae play an important role in the diversity of freshwater and terrestrial algae of North America. About 133 genera are included in Chapter 7, and, using the light microscope, they are characterized by their cytomorphological features and their modes of reproduction. Drawings from the literature together with color photos and a taxonomic key are supplied to help readers identify the algae. Additional remarks on ecology, distribution, methods of investigation, and a rich list of literature references are provided for the reader, giving further information.