Who is Mattie in The Bean Trees?

Mattie is the strong, nurturing widow who owns Jesus is Lord Used Tires, helps Taylor and Turtle when they first arrive in Tucson, and shel­ters Estevan and Esperanza and other Central American refugees in her home. Mattie is a kind of conductor on the underground railroad-like system that locates such refugees-termed "illegal aliens" by the United States government-and gives them sanctuary. Mattie impresses Taylor at first as a "woman with. . . know-how," and as the two women get to know each other, Mattie becomes a surrogate mother to Taylor and surrogate grand­mother to Turtle. Mattie's nurturing personality is also expressed in her garden, "a bright, wild won­derland of flowers and vegetables and auto parts."