Lavender Brown (Jessie Cave) in Harry Potter and the Half-Blood Prince.
puberty does strange things to the harry potter cast.: I was very mad when Lavender Brown was re-cast just so Ron could date a white girl.
If you don't want mosquitoes hanging around, be sure to keep a healthy supply of lavender herb and oil.
The one about Professor McGonagall not being the headmaster isn't true if you read Harry Potter and the Cursed Child
Jessie Cave - As Lavender Brown -- World of Harry Potter list