members of Phaeophyceae (brown algae) store food as complex carbohydrates, which may be in the form of laminarin or mannitol . Ectocarpus is listed as a common member of Phaeophyceae . In contrast, Volvox and Ulothrix are green algae (Chlorophyceae) which store starch , and Gracilaria is a red alga (Rhodophyceae) which stores floridean starch .