Callistemon species are commonly referred to as bottlebrushes because of their cylindrical, brush like flowers resembling a traditional bottle brush. They are found in the more temperate regions of Australia, mostly along the east coast and south-west.
Flower heads vary in colour with species; most are red, but some are yellow, green, orange or white. Each flower head produces a profusion of triple-celled seed capsules around a stem (see picture) which remain on the plant with the seeds enclosed until stimulated to open when the plant dies or fire causes the release of the seeds. (Ref)