The important criteria used
to distinguish the different
algal groups based on the
recent biochemical, physiological
and electron microscopic
studies are :
a) photosynthetic pigments,
b) storage foodproducts,
c) cell wall component,
d) fine structure
of the cell and e) flagella. Accordingly, algae are classified into three main
groups i.e. green (Chlorophyta), brown (Phaeophyta) and red (Rhodophyta).