green algae

green algae Large group of marine and freshwater algae (phylum Chlorophyta). They are distinct from other algae by virtue of possessing cup-shaped chloroplasts that contain chlorophyll b, and by producing cells with flagella at some stage in their lives. Green algae range in size from microscopic single-cell types to large, complex seaweeds. See also lichen

green algae The common name for algae of the division Chlorophyta. Not all members are green; e.g., members of the genera Trentepohlia and Cephaleuros may be orange.

Chlorophyta (green algae) Division of algae which are typically green in colour. In common with higher land plants, green algae include chlorophylls a and b among their principal pigments, have cellulose as the main constituent of cell walls, and form food reserves of starch. Consequently it is believed that the ancestors of land plants must have belonged to this group. The organisms take many forms, ranging from unicellular to relatively complex multicellular plants. They are found today mainly in freshwater habitats and their distribution is cosmopolitan. They are known from the Precambrian onwards, and the earliest eukaryotes were probably of this division. Marine, lime-secreting green algae have contributed to algal limestone reefs since the Cambrian. Fossil genera include Palaeoporella (similar to modern Halimeda), and Coelosphaeridium (similar to modern Acetabularia). See also CHAROPHYCEAE.