Genus with evergreen shrubs and small trees originating from scrubland habitats and woodland environments in Australia. There are around 12 described species that produce bell-shaped flowers. These species readily hybridise with one another in the wild and many cultivars have been produced by botanists. Flowers tend to be red-pink, cream or white-green and hanging singly or in small groups. Foliage is oppositely arranged, consisting of simple leaves with branched hairs on their surface.