Phycology (or algology), a subdiscipline of botany, is the study of algae. Most algae are eukaryotic, photosynthetic organisms that live in a wet environment. They are distinguished from the higher plants by a lack of true roots and leaves. Many species are single-celled and microscopic; many others are multicellular to one degree or another, some of these growing to large size (for example, seaweeds such as kelp). Algae are important as primary producers in aquatic ecosystems. Phycology also includes the study of prokaryotic forms known as blue-green algae or cyanobacteria.

See also Important publications in phycology