Who is Boo Boo Tannenbaum from Nine Stories and what is their importance?

Boo Boo Tannenbaum is described as a small, "stunning" woman of twenty-five. She is married and has one young son, Lionel. She is also the sister of Seymour Glass, who appears in the story "A Perfect Day for Bananafish." Boo Boo and her husband are wealthy. They have an apartment in New York, as well as a lakeside home in Connecticut. Boo Boo is portrayed as a loving, attentive mother.