Metrosideros oreomyrtus (Metrosideros oreomyrtus)

Description

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 Greek metra or "heartwood" and sideron or "iron". Perhaps the best-known species are the p-hutukawa (M. excelsa), northern r-t- (M. robusta), and southern r-t- (M. umbellata) of New Zealand, and --hi-a lehua, (M. polymorpha), from the Hawaiian Islands. Metrosideros is one of the most widely spread flowering plant genera in the Pacific. New Caledonia has 21 species of Metrosideros, New Zealand has 12, New Guinea has seven and Hawaiʻi has 5. The genus is present on most other high Pacific Islands, including Solomon Islands, Vanuatu, Fiji, Samoa, Cook islands, French Polynesia, Bonin Islands and Lord Howe Island, but absent from Micronesia . The genus is also represented by one species in the Philippines, one in South America (Chile and Argentina), and one outlier in South Africa. Metrosideros seeds are very lightweight and easily dispersed by wind. The seeds can also survive freezing temperatures, and up to 30 days submerged in salt water and still germinate. which probably accounts for their wide distribution. They are often found as pioneer trees on lava flows and on mountain ridges. It has always been something of a mystery to Southern Hemisphere botanists that, despite the clear propensity towards long distance dispersal, this genus does not occur in Australia. Metrosideros are often cultivated for their showy flowers, as street trees or in home gardens. The flowers are generally red, but some cultivars have orange, yellow or white flowers. Some names listed in horticultural catalogues and other publications, such as M. villosa and M. vitiensis, are actually the names of varieties or cultivars (usually of M. collina) rather than valid scientific species. The pōhutukawa of New Zealand has several cultivars grown in Australia, Hawaiʻi and California and it has been planted successfully in the north of Spain and on the Scilly Isles off the south-west coast of Britain, but the species is considered an invasive pest in parts of South Africa. Metrosideros kermadecensis is recently naturalised in Hawaiʻi, and has the potential to become a pest. In turn, various cultivars of M. collina and M. polymorpha are widely grown in New Zealand under various names. Metrosideros umbellata occurs naturally south of mainland New Zealand in the Auckland Islands at 50° South latitude, and is the hardiest member of the genus, and a few cultivated specimens are growing in Scotland.