Our heraldic banner was designed in 1967 by Stanford chemistry professor Eric Hutchinson as the symbol for the graduate division. He designed the university flag and the shields of all seven schools at that time. The triple redwood frond represents the three major functions of a university: the discovery, codification, and transmission of knowledge. It appears on the shields and flags of all seven schools and on the Stanford University flag.
The remainder of our banner employs triangles and ermine tails. The triangles symbolize the hoods appropriate for Stanford degrees. The small black design element, the ermine, recalls the ermine-trimmed hood commonly worn by medieval scholars. The seven ermine tails stand for the seven schools offering graduate degrees. Blue is the color of the velvet trim on PhD hoods. White for the arts and gold for science are in the shield of the School of Humanities and Sciences, and gold also appears in the shield of the School of Earth, Energy & Environmental Sciences, recalling Herbert Hoover's mining of gold in Australia.
More detail about the design of the flags and shields can be found in the Stanford Historical Society's journal, Sandstone and Tile (1996).