Charophyta. Mesostigmatophyceae (syn. Chaetosphaeridiophyta) Prasinophytae. Chlorodendrales. Chlorophyta. Streptophyta. Green algae. The green algae (singular: green alga) are the large group of algae from which the embryophytes (higher plants) emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic (and often just known as kingdom Plantae).
The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid and filamentous forms, and macroscopic seaweeds. In the Charales, the closest relatives of higher plants, full differentiation of tissues occurs. There are about 8,000 species of green algae. Many species live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or highly differentiated macroscopic seaweeds. Cellular structure Viridiplantae. Plant. Green plants have cell walls with cellulose and characteristically obtain most of their energy from sunlight via photosynthesis using chlorophyll contained in chloroplasts, which gives them their green color.
Some plants are parasitic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are also characterized by sexual reproduction, modular and indeterminate growth, and an alternation of generations, although asexual reproduction is common. Chloroplastida. Viridiplantae. Viridiplantae (literally "green plants") are a clade comprising the embryophytes (land plants), and the related green algae which are primarily aquatic.   Together with Rhodophyta and glaucophytes, Viridaeplantae are thought to belong to a larger clade called Archaeplastida or Primoplantae.
The monophyletic Chlorophyta and Streptophyta are classified under Viridiplantae.