Some New Zealand lichens have useful chemical and dyeing properties. Sticta coronata, which is found mainly on forest trees and shrubs and sometimes measures more than a foot across – green with purplish patches, and yellow underneath – has yielded polyporic acid, which shows promising effects on leukaemia in mice. Dyes of a wide range of colours can be made from species of Sticta. Usnea, or “Old Man's Beard”, found hanging from old trees and fences, produces dyes in shades of brown and orange.