While both algae and plants are photosynthetic organisms, they store their food in different forms:

* Plants store their food as starch. Starch is a complex carbohydrate made up of glucose molecules linked together.

* Algae store their food as starch (in some species) or as a similar complex carbohydrate called floridean starch (in red algae).

Glycogen is the primary form of carbohydrate storage in animals and fungi, not in plants or algae.