Note: Do not rely on this information. It is very old.
Gulfweed
Gulf-weed, or Sargasso-weed (Sargassum bacciferum), a sea-weed belonging to the order Fucacese, with berry-like air-bladders, but rarely fructifying. An enormous mass of detached pieces of this weed floats in the Atlantic about lat. 20° to 25° N. and long. 40° W. covering over 200,000 square miles, where it was discovered by Columbus.