緑藻
A few other organisms rely on green algae to conduct photosynthesis for them. The chloroplasts in dinoflagellates of the genus "Lepidodinium", euglenids and chlorarachniophytes were acquired from ingested green algae, and in the latter retain a nucleomorph (vestigial nucleus). Green algae are also found symbiotically in the ciliate "Paramecium", and in "Hydra viridissima" and in flatworms. Some species of green algae, particularly of genera "Trebouxia" of the class "Trebouxiophyceae" and "Trentepohlia" (class Ulvophyceae), can be found in symbiotic associations with fungi to form lichens. In general the fungal species that partner in lichens cannot live on their own, while the algal species is often found living in nature without the fungus. "Trentepohlia" is a filamentous green alga that can live independently on humid soil, rocks or tree bark or form the photosymbiont in lichens of the family Graphidaceae. Also the macroalga "Prasiola calophylla" (Trebouxiophyceae) is terrestrial, and