The Standard of Elendil includes the White Tree of Gondor, seven stars, and the crown of Elendil on a black background.
The White Tree that is found by Aragorn (when directed to look by Gandalf) is described as having white blossoms, and Tolkien used five-pointed stars in his own illustrations of the White Tree for Elendil livery. I combined the two ideas here and incorporated star-like blooms as the seven stars on the tree. The crown is my own version inspired by Tolkien's description and illustration.
“And then wonder took [Éomer], and a great joy; and he cast his sword up in the sunlight and sang as he caught it. And all eyes followed his gaze, and behold! upon the foremost ship a great standard broke, and the wind displayed it as she turned towards the Harlond. There flowered a White Tree, and that was for Gondor; but Seven Stars were about it, and a high crown above it, the signs of Elendil that no lord had borne for years beyond count. And the stars flamed in the sunlight, for they were wrought of gems by Arwen daughter of Elrond; and the crown was bright in the morning, for it was wrought of mithril and gold.”
—Excerpt from The Lord of the Rings, book 5 chapter 6, The Battle of Pelennor the Fields.
The crown in the design is inspired by the description from the chapter The Steward and the King from book six of The Lord of the Rings: an ancient crown, “shaped like the helms of the Guards of the Citadel, save that it was loftier, and it was all white, and the wings at either side were wrought of pearl and silver in the likeness of the wings of a sea-bird, for it was the emblem of kings who came over the Sea; and seven gems of adamant were set in the circlet; and upon its summit was set a single jewel the light of which went up like a flame.” Tolkien himself sketched this crown (illustration below), however I deviated from his sketch to create something more reminiscent of a classic crown shape, combined with the elements described in the text.
