Ulothrix is a member of Chlorophyceae (green algae) , and members of this class store food as starch . Mannitol is a stored food found in Phaeophyceae (brown algae) . The other options are correctly matched: Volvox (green alga) stores starch; Ectocarpus (brown alga) contains the pigment fucoxanthin ; and Porphyra (red alga) stores food as Floridean starch .