Archaeplastida
Together, red algae, green algae, and land plants make up the fourth eukaryotic group which is called Archeaplastida. Archeaplastida is monophyletic group that descended from the ancient protist that engulfed a cyanobacterium. Red algae and green algae include unicellular species, colonial species, and multicellular species. Many of the large algae knownn informally as "seaweeds" are multicellular red or green algae. Protists in Archeaplastida include key photosynthetic species that form the base of the food web in some aquatic communities. The cells of the Archeaplastida typically lack centrioles and have mitochondria with flat cristae. There is usually a cell wall including cellulose and food