Cather uses the flowers as symbols in "Paul's Case". Explain the symbolism of the flowers in the following instances: The red carnation in Paul’s lapel when he appears before the faculty. When Paul approaches his house at night and thinks about flowers. When Paul sees the flowers blooming behind the glass. When Paul’s carnation droop because of the cold.
It is also significant that the flowers represent artificiality: the flowers Paul sees as he rides through New York are growing under glass, in an artificial environment. Paul tends to find natural things (or flowers in their natural state) ugly and observes that "the natural nearly always wore the guise of ugliness." This is significant because Paul can't love himself as he is. Rather, he loves and nurtures the artificial illusion of himself that he creates.
The flower in Paul's lapel is his attempt to be something he is not--to appear flippant and "better than" his teachers, to show that he doesn't care about being disciplined. Later, when the flower begins to droop, it is as if the brief period of glory Paul experiences is also ending. He remembers the flowers under glass and thinks that they, too, have faded by now, having experienced evanescent glory. His final act of burying the flower under the snow, of course, foreshadows Paul's own death.
Paul believes that he appears more beautiful in his new attire and way of living though it is all false--artificial. The tragedy of this story is that Paul is never able to learn who he really is and to love that person.
The flowers that appear consistently in the story represent Paul trying to see and find beauty in a very mundane, uncertain world. When he wears the red rose when he appears before the faculty, it stands out in a negative way, appearing garish and tacky instead of beautiful and subtle. Another example is when the carnation wilts towards the end of the story. He buries the carnation in the snow, which can be symbolic of his own death. He is burying himself in many ways, along with this hopes and his dreams:
They also symbolize Paul, who, like flowers in winter, is out of place. The flower-killing snow Paul sees on the train to New York and by the railroad tracks at the story's end provide a stark contrast to the bright flowers Paul surrounds himself with. (eNotes)
The flower also symbolizes Paul's trip to New York at the end of the story. He is aware that it is a temporal fling and that in a short period it will be over. Nonetheless, he indulges in it as his beautiful, albeit transient, moment of life. Just like the red carnation that he loves so much. The flower is already dead so its beauty is temporary. In just a day or two the cut flower will start to resemble its reality and its petals will turn brown and shrivel. Similarly, Paul's trip is beautiful while he is living it, but it is not his reality. He is allowing himself to be deceived so that he can experience what he feels he wants out of life.