Who is Lady Wu, Lily's mother from Snow Flower and the Secret Fan and what is their importance?

This character is not developed as fully as some of the others, but we learn that Lily's mother, born under the sign of the monkey, will do whatever it takes to try to advance her family, and will keep secrets and tell lies if necessary to get ahead. Lily realizes that any love her mother has shown her has been a means to her own end, and it is not clear whether her mother is even capable of loving. She is rigid in her determination to follow the rules set down for women of her class and wants the same for her daughters.