Colors
Susan, G, dark.
Vague spoilers for Last Battle.
Susan disregards the meaning of the colors.
She leaves a deep yellow rose for Peter, because it reminds her of his lion's-mane golden hair.
Blood-red for Lucy, because it looks like her sister's cordial. Susan thinks maybe the similarly-colored rose will bring her back.
Off-white for Edmund, and she thinks it matches the color of his skin.
Except, she doesn't quite remember the color of Peter's hair, or Lucy's cordial, or Edmund's skin anymore. She can only guess.
(So she heeds the meaning of colors, buys a white and a red rose for herself, because she knows it means unity.)