Who is Aunt Annie from Crow Lake and what is their importance?

Aunt Annie is Mr. Morrison's single sister. Annie lives with her father and cares for him while he works the farm. Aunt Annie is the one who comes to stay with the children after their parents' deaths because she is the only one who is free enough to go. Aunt Annie takes charge of the household and arranges for the children to be sent to separate family farms so that Luke might go to teacher's college, but is overruled when Luke decides to take custody of the children. Aunt Annie cares deeply for the children and worries about their welfare but is forced to leave them in Luke's custody. Katie writes to Annie until her death, keeping her informed of their progress.