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EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > PLANTS > MACROALGAE (SEAWEEDS)

Definition:
Macroalgae, or seaweeds, are the dominant marine plants inhabiting
temperate coasts. Macroalgae contain chlorophyll and an assortment of
additional pigments spanning the visible spectrum from blue to red.
Historically, classification was based on pigmentation. At present, the
classification of marine algae relies on additional diagnostic
characteristics. Although pigmentation is only one of the characteristics
used to classify the algae, the original names, which were based on color,
have been retained. The major divisions of seaweed are green
algae (Chlorophyta), red algae (Rhodophyta), and brown algae
(Phaeophyta). 


Reference:
Lerman, Matthew. 1986. Marine Biology. The Benjamin Cummings Publishing
Company. Menlo Park, California.