Phycologists consider seaweed to refer any of a large number of marine benthic algae that are multicellular, macrothallic (large-bodied), and thus differentiated from most algae that tend towards microscopic size (Smith, 1944). Seaweeds are found among the green, red, and brown algae. Some cyanobacteria may also be counted as seaweeds. Seaweeds are named after terrestrial "weeds", and are not to be confused with things like seagrass which are vascular plants and not algae.
thallus: the algal body
- blade: a flattened structure that is somewhat leaf-like
- stipe: a stem-like structure
- holdfast: specialized basal structure providing attachment to the bottom
- Smith, G.M. 1944. Marine Algae of the Monterey Peninsula, California. Stanford Univ., 2nd Edition.
- The Seaweed Site , information on all aspects of seaweeds and marine algal biology