Large, robust forms of brown algae (PHAEOPHYCEAE) in the order Laminariales. They are a major component of the lower intertidal and sublittoral zones on rocky coasts in temperate and polar waters. Kelp, a kind of SEAWEED, usually refers to species in the genera LAMINARIA or MACROCYSTIS, but the term may also be used for species in FUCUS or Nereocystis.

A genus of BROWN ALGAE in the family Lessoniaceae, and one of the major forms of KELP. The species Macrocystis pyrifera, also known as giant kelp, is the largest of the marine algae.

Those nucleic acid sequences that function as units of heredity which are located within the CHLOROPLAST DNA.