A large phylum (or group, i.e. the chlorophytes) comprising most of the green algae. They possess chlorophylls a and b, store food reserves as starch, and have cellulose cell walls. In these respects, and on the basis of molecular studies, they are now regarded as the sister group of the streptophytes (or charophytes), which includes the land plants and certain freshwater algae, i.e. the stoneworts and choleochaetophytes. Chlorophytes are widely distributed and diverse in form. Unicellular forms may occur singly (sometimes with flagella for motility) or in colonies, while multicellular forms may be filamentous (e.g. Spirogyra) or platelike (e.g. Ulva).