A class of the subphylum Sarcomastigophora, also known as the Phytomastigina. These are the plant flagellates which contain chlorophyll and other pigments, but colorless forms are also included. Grass green is the usually observed color, primarily because the green flagellates are the largest. Those containing an excess of yellow pigments generally are smaller, and fewer species have unusual colors, such as blue or red. Holophytic, saprophytic, and holozoic modes of nutrition occur, and specific chemical components may be demanded by individual species within the group.