Economically Important Seaweeds

The plants in the sea other than seagrasses—what we call seaweeds—belong to the simplest group of plants; the marine algae. With few exceptions, these plants are so simple that they have no distinguishable roots, stems or leaves. The algae vary in size from microscopic single-celled forms (eg. diatoms) to the giant macrophytes of temperate waters (Macrocystis, Nereocystis, etc).