Harry Potter and the Order of the Phoenix
Lavender is a Gryffindor fifth year girl. Like her friend Parvati, she adores astrology and worships Professor Trelawney. But she has even less to do in Book 5 than Parvati does. She does go along with Parvati to bring Professor Trelawney some daffodils. She reports that Professor Trelawney "was crying and saying she'd rather leave the castle for ever than stay here where Umbridge is, and I don't blame her. Umbridge was horrible to her, wasn't she?" (27.10). And that's pretty much all Lavender has to contribute.