As a matter of fact, the flowers could be interpreted to represent
Paul throughout the story. Paul feels that he does not belong in his life,
that he was destined for finer things than to be stuck in the run-down
dreary drab house on Cordelia Street. When Paul walks to within view of
his house, he thinks of things that he would rather see than the "common
food, of house permeated with kitchen odors." Instead Paul had "a morbid
desire for cool things and soft lights and fresh flowers." In this
thought Paul decides that fresh flowers do not belong in the house, just
as he doesn't belong in the house.
The first night Paul stays in New York City, he passes a flower shop
which was displaying bright bouquets of flowers that reminded Paul of the
joyous mood he was in. This was largely due to the fact that it had been
snowing rather hard in the city as he passed the shop and he realized how
much more lovely and how much brighter the blossoms seemed when compared
to the stark whiteness of the snow.
Paul identified with flowers so much that he sent the bellboy down to get him a bouquet of flowers when he noticed that his otherwise perfect room at the Waldorf hotel was lacking them. Paul seemed to feel that this hotel room was far more worthy of having fresh flowers in it than his house. He felt that the room needed them for the simple reason that the room deserved them.
Paul refers to the flowers in the shop window again as he looks back on his week before he dies. He notices that the carnations that he had in his buttonhole were wilting from the cold weather and reflects on the fact that the flowers that he saw the first night had long since wilted and died as well. When he realizes this, he compares himself to the flowers implicitly.
"The carnations in his coat were drooping with cold, he noticed; their red glory over. It occurred to him that all the flowers he had seen in the shop windows that first night must have gone the same way, long before this. It was only one splendid breath they had, in spite of their brave mockery at the winter outside the glass. It was a losing game in the end, it seemed, this revolt against the homilies by which this world is run. Paul took one of the blossoms carefully from his coat and scooped a little hole in the snow, where he covered it up." Paul's Case, Willa Cather.
This is the most profound glance into Paul's soul in the whole story. Paul is the flowers. He had been drooping in the cold as well because he was walking along the tracks waiting for the train to pass. He realizes here that he was one of the flowers blooming in the shop window while in New York City, mocking the winter that his previous life had been, and that he thought he put behind him. His "one splendid breath" was the entire week in New York City living the life he never thought he would lead. He was revolting against the nastiness of the world and he failed to make a permanent change on his life. If he had not killed himself, he would have returned to his terrible non-life, even the worse for knowing what it is like to have a life. When he buried the flower, he signified that he was going to bury another wilted flower, himself. His body was just as delicate compared to the oncoming locomotive as the flowers compared to his hands.