Green Bough of Return
The Green Bough of Return was a branch from the Fragrant Tree Oiolairë which was placed at the prow of the Númenórean ships as a symbol of good fortune (and as a token of friendship with Ossë and Uinen). By custom, the bough had to be brought by a female, often a close relative of the captain.
When Aldarion, the son of Tar-Meneldur, finished the great ship Palarran and purposed to go to sea, his father forbade any of his family to bring the bough to his ship. Erendis performed this rite and on that day Aldarion fell in love with her.
Later though, when Erendis had become the wife of Tar-Aldarion and estranged from him, she refused to bring the bough as a show of disagreement with her husband's frequent voyages towards Middle-earth. Therefore on the prow of Aldarion's later ship Hirilondë the image of an eagle stood, and not the Green Bough of Return.