It is attached to the surface of rocks by a structures called a holdfast . The chloroplast of the red algae show strong evidence of descent from cyanobacteria. The arrangement of photosynthetic membranes are similar. Red algae stores their food as floridean starch. No red algae has flagella, even in sperm cells.
Most red algae are marine, with a few freshwater and terrestrial forms.
The ancestors of all plants were undoubtedly members of phylum Chlorophyta. Green algae show great diversity of form and live in a variety of habitats. There is no tissue differentiation. The chloroplasts of algae contain chlorophylls a and b as well as beta carotene. They store their food as starch.