The flowers that Nathaniel gives to Mattie represent hope. Nathaniel doesn't want Mattie to forget him, and it's Mattie's memories prior to the breakout of yellow fever that keep her going through the hard times. When Mattie's mom, Lucinda, contracts yellow fever, she's brought to the coffeehouse in a wheelbarrow, representing the fear people felt during this epidemic. For some, a crisis such as this brings out the worst in society, such as throwing the dead bodies in the streets.
This story is about Mattie's maturation into adulthood, and some of the characters help Mattie to become a woman. Although Lucinda, Mattie's mom, is hard on her, Lucinda gives Mattie perseverance, the ability to never give up, to keep going no matter what the odds are. Mattie's grandfather symbolizes self-confidence, giving Mattie the power to believe in herself and to do what's right. Eliza, Lucinda's friend, picks up where Mattie's grandfather left off, allowing Mattie to realize her own value to those around her. Nell, the little girl Mattie finds and decides to take care of, symbolizes a better future for all of them. She depends on Mattie as a mother, and this symbolizes Mattie's completion of her journey into adulthood.