A division of typically unicellular protists, sometimes regarded as algae, sometimes as protozoa (class Phytomastigophora). They are characterized by the possession of a single flagellum, the formation of paramylum as a storage product, possession of chlorophylls a and b, and the absence of sexual reproduction. Vegetative cells lack a cell wall but possess a proteinaceous pellicle. There are many genera, the best known of which is Euglena. They are found in a wide range of aquatic habitats: ditches, ponds, puddles, and rivers (especially those polluted with organic matter). Some species occur in brackish or marine waters.
Subjects: Plant Sciences and Forestry.