Julian's mother sits next to this woman on the bus. All we know about her is that she has protruding teeth and long yellow hair—and that she has a son, she's probably racist, and she's definitely poor.
How can we be sure about this? She complains about the heat of her apartment (she can't afford fans or any cooling system) and trying to keep her son in line. (She tells a story about boys in her neighborhood stealing car tires—definitely not what respectable young men do.)
The fact that Julian's mom is perfectly happy to strike up a conversation with her, though, shows that she might not be quite as high-and-mighty as she pretends to be. She's actually a pretty friendly lady. As long as you're white.