members of the division Rhodophyta (about 4,100 species), predominantly marine algae often found attached to other shore plants. Their morphological range includes filamentous, branched, feathered, and sheetlike thalli. In most species, thin protoplasmic connections provide continuity between cells. Their usual red or blue colour is the result of a masking of chlorophyll by phycobilin pigments (phycoerythrin and phycocyanin).
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