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Related to green alga: Filamentous algae
Any of numerous mostly freshwater algae, such as spirogyra and sea lettuce, that usually have chlorophyll unmasked by other pigments. The green algae traditionally comprised the division Chlorophyta but are now thought to consist of more than one evolutionary lineage.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.