Metra — middle or heart of tree, sideros — iron, referring to the hard wood of the genus.
Shrubs, trees and woody climbers. Leaves simple, opposite, gland-dotted; stipules absent. Flowers in terminal or axillary clusters (rarely solitary), white, pink and yellow but mostly red. Sepals and petals 5. Stamens numerous, much longer than the petals. Ovary 3-chambered. Fruit capsule leathery, loculicidally dehiscent from 3 valves.
Grown for the spectacular and prolific bottlebrush flowers and neat aromatic leaves. A number of cultivars are listed including 'Gala', 'Gold Bond', 'Rangitoto' and 'Tahiti'.
About 50 species from Australia, New Zealand to Polynesia and Malaya and 1 species from S Africa.
Seed or cuttings.
Some species are a source of timber, especially in New Zealand; sometimes used medicinally by the Maoris.
Differs from Callistemon in having opposite leaves and branched flower clusters.
Source: (2002). Myrtaceae. In: . Horticultural Flora of South-eastern Australia. Volume 3. Flowering plants. Dicotyledons. Part 2. The identification of garden and cultivated plants. University of New South Wales Press.