What is the vital discovery that Lily makes in this chapter. Why is this so surprising?

Lily sees a picture matching her mother’s black Mary on jars of honey labeled “Black Madonna Honey.” When Lily asks about the picture, the storeowner explains that the owner of the honey company is a black woman, August Boatwright, who lives in the bright pink house. Lily tells Rosaleen, and Rosaleen worries that Lily is getting her hopes up. It is surpeising that Lily should find a link to her mother in this store.