Algae (seaweed)

Though widely considered as simple marine plants, seaweeds are actually plant-like organisms called algae. They do not have true stems, leaves, flowers or fruits, or roots, instead anchoring themselves to rocks by root-like holdfasts. They form the basis of the food chain in the marine environment, using energy from sunlight to make food. Although seaweeds are divided into three colour groups (green, brown and red), they are not always true to the group, as classification is based on their history and type of reproduction, rather than colour.