Thallophyta members are classified into three main classes, namely, Chlorophyceae, Phaeophyceae, and Rhodophyceae. The following are the salient features of red algae:
I. They have no motile stage in their life cycle. Flagella are altogether absent.
II. Cell wall is made up of cellulose, and other polysaccharides like agar, carrageenan, etc.
III. The major pigments involve are chlorophyll-a, chlorophyll-d, phycobilins like phycoerythrin.
IV. Inside the thylakoid, there is a single granum.
V. Stored food is a complex polysaccharide, like Floridean starch.