Not sure why this plain is called hawthorn plain as I didn't see any hawthorn trees or bushes. On the other hand, I wasn't actually concentrating on the flora of the plain, so they might have been some there.
Hawthorn was traditionally used for heart disease, digestion, blood circulation, and kidney and bladder problems. It's 'haws' (the red berries) are also powerful antioxidants and can be eaten raw, or as a tea or tincture.