macrocystis pyrifera

from The Collaborative International Dictionary of English v.0.48

Kelp \Kelp\ (k[e^]lp), n. [Formerly kilpe; of unknown origin.]
   1. The calcined ashes of seaweed, -- formerly much used in
      the manufacture of glass, now used in the manufacture of
      iodine.
      [1913 Webster]

   2. (Bot.) Any large blackish seaweed.
      [1913 Webster]

   Note: {Laminaria} is the common kelp of Great Britain;
         {Macrocystis pyrifera} and {Nereocystis Lutkeana} are
         the great kelps of the Pacific Ocean.
         [1913 Webster]

   {Kelp crab} (Zool.), a California spider crab ({Epialtus
      productus}), found among seaweeds, which it resembles in
      color.

   {Kelp salmon} (Zool.), a serranoid food fish ({Serranus
      clathratus}) of California. See {Cabrilla}.
      [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Macrocystis \Mac`ro*cys"tis\, n. [NL. See {Macro-}, and {Cyst}.]
   (Bot.)
   An immensely long blackish seaweed of the Pacific
   ({Macrocystis pyrifera}), having numerous almond-shaped air
   vessels.
   [1913 Webster]