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Rhodophyceae


Rhodophyta are commonly called red algae because of the predominance
of the red pigment, r-phycoerythrin in their body. Majority of the red
algae are marine with greater concentrations found in the warmer areas.
They occur in both well-lighted regions close to the surface of water and
also at great depths in oceans where relatively little light penetrates.
The red thalli of most of the red algae are multicellular. Some of them
have complex body organisation. The food is stored as floridean starch
which is very similar to amylopectin and glycogen in structure.
The red algae usually reproduce vegetatively by fragmentation. They
reproduce asexually by non-motile spores and sexually by non-motilegametes. Sexual reproduction is oogamous and accompanied by complex  post fertilisation developments. The common members are: Polysiphonia, Porphyra , Gracilaria and Gelidium.
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