One of a series of books covering the large, well-defined group of fresh water and essentially unicellular plants, belonging to the green algae. This volume describes all the Saccoderm and some of the Placoderm desmids (genera Actinotaenium, Cosmarium, Cosmocladium, Spinocosmarium, and Xanthidium), a total of 218 taxa. There are keys for identifying the genera and species, an annotated list of habitats, some ecological comments, a large number of literature references, and seven ecological data tables. The preface includes an account of the morphology of the desmid cell (with text figures), and a brief history of freshwater phycology in New Zealand.