In
Hawaii 70% of the algal species are in the Rhodophyta.
They have a Diverse
Distribution & range from Tropical
to Cold Waters. Some Red Algae
can be found in Cold Fast Running Freshwater Streams.
They,consequently have the Greatest Range for
Macroalgae.
Calloglossa: a freshwater species
They can be found at depths up to 120m
A few species are Terrestrial
Cell Wall
Inner Cellulose Wall
Random
Cellulose Fibrils
Granular Matrix
Geniculate Coralline Rhodophyta
Outer Sheath = Colloidal Substances
Agar (Commercially Important)
Carrageenan (Commercially
Important)
Others
Geniculate Coralline Alga
Coralline Algae
These precipitate Calcium Carbonate in their Outer
Wall Layers. This forms a rigid extracellular matrix that contributes to the formation of
Coral Reefs. There are two general types based on their morphology. These are called Geniculate and Non-Geniculate.
Geniculate -> Branched & Flexible due to the presence of
Genicula between rigid Intergeniculate segments.
Non-Geniculate -> These are encrusting and are generally
prostrate. However some produce small
Rhodophyta-1 
