Metrosideros is a genus of approximately 60 trees, shrubs, and vines mostly found in the Pacific region in the Myrtaceae family. Most of the tree forms are small, but some are exceptionally large, the New Zealand species in particular. The name derives from the Ancient Greekmetra or "heartwood" and sideron or "iron". Perhaps the best-known species are the pohutukawa (M. excelsa), northern rata (M. robusta), and southern rata (M. umbellata) of New Zealand, and ohia lehua, (M. polymorpha), from the Hawaiian Islands.