Metrosideros
Encyclopedia
Metrosideros is a genus of approximately 50 tree
s, shrub
s, and vine
s native to the islands
of the Pacific Ocean
, from the Philippines
to New Zealand
and including the Bonin Islands, Polynesia
, and Melanesia
, with an anomalous outlier in South Africa
. 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 pōhutukawa
, (M. excelsa), northern rātā
(M. robusta), and southern rātā
(M. umbellata) of New Zealand, and ōhia lehua
, (M. polymorpha), from the Hawaiian Islands
.
has 21 species of Metrosideros, New Zealand
has twelve, Hawaii
has five, and Papua
has four. The remainder are scattered across small islands
of the Pacific, with one outlier described from South Africa
. Metrosideros seeds can disperse on the wind, which accounts for their wide distribution from a presumed origin in a greater New Zealand continent, which at the time of the breakup of Gondwana
in the late Cretaceous
, included New Caledonia. How the genus reached Hawaii appears puzzling because the prevailing trade wind
s blow from the east. However high altitude wind patterns may have brought seeds north from the Marquesas Islands
, which molecular evidence suggests as the origin of the Hawaiian species from a single colonising event (the Hawaiian M. polymorpha
is similar to the widespread M. collina found in the Marquesas Islands
, and was long classified as a subspecies of it). Considering that the group likely spread north and east from New Zealand, counter to prevailing ground-level winds, this is not surprising.
of New Zealand has several cultivars grown in Australia, Hawaii 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 Hawaii, 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 50º South latitude, and is the hardiest member of the genus, and a few cultivated specimens are growing in Scotland
.
) and vines, with red, pink or white flowers; Metrosideros, 26 species, trees and shrubs, flowers mostly red, but some species have yellow or white flowers; and Carpolepis, 3 species of hemi-epiphytic
rainforest trees from New Caledonia
, all with bright yellow flowers.
subgenus Metrosideros
subgenus Mearnsia
subgenus Carpolepis
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s, and vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
s native to the islands
Pacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, from the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
to New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and including the Bonin Islands, Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...
, and Melanesia
Melanesia
Melanesia is a subregion of Oceania extending from the western end of the Pacific Ocean to the Arafura Sea, and eastward to Fiji. The region comprises most of the islands immediately north and northeast of Australia...
, with an anomalous outlier in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. 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 pōhutukawa
Pohutukawa
The Pōhutukawa is a coastal evergreen tree in the myrtle family, Myrtaceae, that produces a brilliant display of red flowers made up of a mass of stamens. The Pōhutukawa is one of twelve Metrosideros species endemic to New Zealand...
, (M. excelsa), northern rātā
Metrosideros robusta
Northern rātā , is a huge forest tree endemic to New Zealand. It grows up to 25 m or taller, and usually begins its life as a hemiepiphyte high in the branches of a mature forest tree; over centuries the young tree sends descending and girdling roots down and around the trunk of its host,...
(M. robusta), and southern rātā
Metrosideros umbellata
Southern rātā , is a tree endemic to New Zealand. It grows up to 15 m. or more tall with a trunk up to 1 m. or more in diameter. It produces masses of red flowers in summer...
(M. umbellata) of New Zealand, and ōhia lehua
Metrosideros polymorpha
The ōhia lehua is a species of flowering evergreen tree in the myrtle family, Myrtaceae, that is endemic to the six largest islands of Hawaii. It is a highly variable tree, being tall in favorable situations, and much smaller when growing in boggy soils or on basalt...
, (M. polymorpha), from the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
.
Distribution
New CaledoniaNew Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
has 21 species of Metrosideros, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
has twelve, Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
has five, and Papua
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
has four. The remainder are scattered across small islands
Pacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
of the Pacific, with one outlier described from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. Metrosideros seeds can disperse on the wind, which accounts for their wide distribution from a presumed origin in a greater New Zealand continent, which at the time of the breakup of Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
in the late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, included New Caledonia. How the genus reached Hawaii appears puzzling because the prevailing trade wind
Trade wind
The trade winds are the prevailing pattern of easterly surface winds found in the tropics, within the lower portion of the Earth's atmosphere, in the lower section of the troposphere near the Earth's equator...
s blow from the east. However high altitude wind patterns may have brought seeds north from the Marquesas Islands
Marquesas Islands
The Marquesas Islands enana and Te Fenua `Enata , both meaning "The Land of Men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. The Marquesas are located at 9° 00S, 139° 30W...
, which molecular evidence suggests as the origin of the Hawaiian species from a single colonising event (the Hawaiian M. polymorpha
Metrosideros polymorpha
The ōhia lehua is a species of flowering evergreen tree in the myrtle family, Myrtaceae, that is endemic to the six largest islands of Hawaii. It is a highly variable tree, being tall in favorable situations, and much smaller when growing in boggy soils or on basalt...
is similar to the widespread M. collina found in the Marquesas Islands
Marquesas Islands
The Marquesas Islands enana and Te Fenua `Enata , both meaning "The Land of Men") are a group of volcanic islands in French Polynesia, an overseas collectivity of France in the southern Pacific Ocean. The Marquesas are located at 9° 00S, 139° 30W...
, and was long classified as a subspecies of it). Considering that the group likely spread north and east from New Zealand, counter to prevailing ground-level winds, this is not surprising.
Cultivation
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 catalogs 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 pōhutukawaPohutukawa
The Pōhutukawa is a coastal evergreen tree in the myrtle family, Myrtaceae, that produces a brilliant display of red flowers made up of a mass of stamens. The Pōhutukawa is one of twelve Metrosideros species endemic to New Zealand...
of New Zealand has several cultivars grown in Australia, Hawaii and California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
and it has been planted successfully in the north of Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
and on the Scilly Isles off the south-west coast of Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, but the species is considered an invasive pest in parts of South Africa. Metrosideros kermadecensis
Metrosideros kermadecensis
Metrosideros kermadecensis, commonly called the is an evergreen tree of the myrtle family which is endemic to the volcanic Kermadec Islands about 900 km north-east of New Zealand. The tree produces a brilliant display of red flowers, made up of a mass of stamens and is the dominant forest tree on...
is recently naturalised in Hawaii, 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
Metrosideros umbellata
Southern rātā , is a tree endemic to New Zealand. It grows up to 15 m. or more tall with a trunk up to 1 m. or more in diameter. It produces masses of red flowers in summer...
occurs naturally south of mainland New Zealand in the Auckland Islands
Auckland Islands
The Auckland Islands are an archipelago of the New Zealand Sub-Antarctic Islands and include Auckland Island, Adams Island, Enderby Island, Disappointment Island, Ewing Island, Rose Island, Dundas Island and Green Island, with a combined area of...
at 50º South latitude, and is the hardiest member of the genus, and a few cultivated specimens are growing in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
.
Metrosideros species
There are approximately 50 species of Metrosideros, in three subgenera: Mearnsia, 24 or 25 species, trees, shrubs (some epiphyticEpiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
) and vines, with red, pink or white flowers; Metrosideros, 26 species, trees and shrubs, flowers mostly red, but some species have yellow or white flowers; and Carpolepis, 3 species of hemi-epiphytic
Hemiepiphyte
A hemiepiphyte is a plant which begins its life as an epiphyte but which later grows roots down into the ground. The seeds of hemiepiphytes germinate in the canopy and initially live epiphytically...
rainforest trees from New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
, all with bright yellow flowers.
subgenus Metrosideros
- M. bartlettiiMetrosideros bartlettiiBartlett's rātā , or the Cape Reinga white rātā, is one of twelve Metrosideros species endemic to New Zealand and is notable for its extreme rarity and its white flowers, somewhat uncommon in that genus of red-flowered trees and plants...
J.W.Dawson - Bartlett's rātā (New Zealand) - M. boninensis (Bonin Islands)
- M. cherrieri (New Caledonia)
- M. collinaMetrosideros collinaMetrosideros collina is a species of flowering plant in the family Myrtaceae. It is native to the Marquesas Islands, Society Islands, Fiji and Vanuatu. In the Samoa Islands, the plant is indigenous to the islands of Savai'i, Upolu and Tutuila.-Taxonomy:The species was first formally described by...
(from VanuatuVanuatuVanuatu , officially the Republic of Vanuatu , is an island nation located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is some east of northern Australia, northeast of New Caledonia, west of Fiji, and southeast of the Solomon Islands, near New Guinea.Vanuatu was...
in the southwest to French PolynesiaFrench PolynesiaFrench Polynesia is an overseas country of the French Republic . It is made up of several groups of Polynesian islands, the most famous island being Tahiti in the Society Islands group, which is also the most populous island and the seat of the capital of the territory...
in the east) - M. engleriana (New Caledonia)
- M. excelsa Gaertn.Joseph GaertnerJoseph Gaertner was a German botanist, best known for his work on seeds, De Fructibus et Seminibus Plantarum ....
- Pōhutukawa (New Zealand) - M. gregoryi (SamoaSamoaSamoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...
) - M. humboldtiana (New Caledonia)
- M. kermadecensisMetrosideros kermadecensisMetrosideros kermadecensis, commonly called the is an evergreen tree of the myrtle family which is endemic to the volcanic Kermadec Islands about 900 km north-east of New Zealand. The tree produces a brilliant display of red flowers, made up of a mass of stamens and is the dominant forest tree on...
- Kermadec pōhutukawa (Kermadec IslandsKermadec IslandsThe Kermadec Islands are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga...
) - M. macropusMetrosideros macropusLehua mamo , is a species of tree in the eucalyptus family, Myrtaceae. It is endemic to the island of Oahu in the Hawaiian Islands. It is closely related to the widespread and highly variable ōhia lehua , found throughout the islands. Lehua mamo, however, is only found in the Koolau mountains. ...
A.GrayAsa Gray-References:*Asa Gray. Dictionary of American Biography. American Council of Learned Societies, 1928–1936.*Asa Gray. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998.*Asa Gray. Plant Sciences. 4 vols. Macmillan Reference USA, 2001....
- Lehua mamo (OahuOahuOahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
in Hawaii) - M. microphylla (New Caledonia)
- M. nervulosa (Lord Howe IslandLord Howe IslandLord Howe Island is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, directly east of mainland Port Macquarie, and about from Norfolk Island. The island is about 11 km long and between 2.8 km and 0.6 km wide with an area of...
) - M. nitida (New Caledonia)
- M. ochrantha (Fiji)
- M. oreomyrtus (New Caledonia)
- M. polymorphaMetrosideros polymorphaThe ōhia lehua is a species of flowering evergreen tree in the myrtle family, Myrtaceae, that is endemic to the six largest islands of Hawaii. It is a highly variable tree, being tall in favorable situations, and much smaller when growing in boggy soils or on basalt...
Gaudich.Charles Gaudichaud-BeaupréCharles Gaudichaud-Beaupré was a French botanist.He was born in Angoulême, the son of J-J. Gaudichaud and Rose Gaudichaud. He studied pharmacology at Cognac and Angoulême. He also studied chemistry and herbology.His greatest claim to fame was serving as botanist on a circumglobal expedition from...
- Ōhia lehua (Hawaii) - M. punctataMetrosideros punctataMetrosideros punctata is a species of plant in the Myrtaceae family. It is endemic to New Caledonia. It is threatened by habitat loss.-References:* Jaffré, T. et al. 1998. . Downloaded on 22 August 2007....
(New Caledonia) - M. robustaMetrosideros robustaNorthern rātā , is a huge forest tree endemic to New Zealand. It grows up to 25 m or taller, and usually begins its life as a hemiepiphyte high in the branches of a mature forest tree; over centuries the young tree sends descending and girdling roots down and around the trunk of its host,...
A.Cunn.Allan Cunningham (botanist)Allan Cunningham was an English botanist and explorer, primarily known for his travels in New South Wales to collect plants.- Early life :...
- Northern rātā (New Zealand) - M. rugosaMetrosideros rugosaMetrosideros rugosa , is a tree of the myrtle family which is endemic to the island of Oahu in the Hawaiian Islands. It is closely related to the widespread and highly variable ōhia lehua , found throughout the islands...
A.Gray - Lehua papa (Oahu in Hawaii) - M. salomonensis (Solomon IslandsSolomon IslandsSolomon Islands is a sovereign state in Oceania, east of Papua New Guinea, consisting of nearly one thousand islands. It covers a land mass of . The capital, Honiara, is located on the island of Guadalcanal...
; this species has been variously placed in both subgenera) - M. sclerocarpa (Lord Howe Island)
- M. tetrasticha (New Caledonia)
- M. tremuloides - Lehua āhihi (Oahu in Hawaii)
- M. umbellataMetrosideros umbellataSouthern rātā , is a tree endemic to New Zealand. It grows up to 15 m. or more tall with a trunk up to 1 m. or more in diameter. It produces masses of red flowers in summer...
Cav.Antonio José CavanillesAntonio José Cavanilles was a leading Spanish taxonomic botanist of the 18th century. He named many plants, particularly from Oceania, his name is abbreviated as Cav...
- Southern rātā (New Zealand) - M. waialeaiae (KauaiKauaiKauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...
in Hawaii)
subgenus Mearnsia
- M. albiflora (New Zealand)
- M. angustifolia (South Africa)
- M. brevistylis (New Caledonia)
- M. cacuminum (New Caledonia)
- M. carmineaMetrosideros carmineaMetrosideros carminea is a forest liane or vine endemic to New Zealand. It occurs in coastal and lowland forest from Te Paki in the north of the North Island south to Mahia Peninsula and Taranaki...
W.R.B.Oliv. - Carmine rātā (New Zealand) - M. colensoi (New Zealand)
- M. cordata (New Guinea)
- M. diffusa (New Zealand)
- M. dolichandra (New Caledonia)
- M. fulgensMetrosideros fulgensMetrosideros fulgens is a forest liane or vine endemic to New Zealand. It occurs in coastal and lowland forest throughout the North Island and on the west coast of the South Island...
Sol. ex Gaertn. - Scarlet rātā (New Zealand) - M. halconensis (Philippines)
- M. longipetiolata (New Caledonia)
- M. operculataMetrosideros operculataMetrosideros operculata is a species of flowering plant in the family Myrtaceae. It is endemic to New Caledonia. It usually grows as a shrub to 3 metres in height, or rarely as a small tree to 10 metres. Stems are square in section and covered with silky hairs. The stiff, pointed leaves have a...
(New Caledonia) - M. ovata (New Guinea)
- M. paniensis (New Caledonia)
- M. parkinsonii (New Zealand)
- M. patens (New Caledonia)
- M. perforataMetrosideros perforataMetrosideros perforata , is one of twelve Metrosideros species endemic to New Zealand. An example of a specific location of occurrence is within New Zealand's Hamilton Ecological District in association with such alliant understory plants as Blechnum discolor, Blechnum filiforme and Doodia media....
(New Zealand) - M. porphyrea (New Caledonia)
- M. ramiflora (New Guinea)
- M. rotundifolia (New Caledonia)
- M. scandens (New Guinea)
- M. whitakeri (New Caledonia)
- M. whiteana (New Guinea)
- M. n. sp. (un-named) (Solomon IslandsSolomon IslandsSolomon Islands is a sovereign state in Oceania, east of Papua New Guinea, consisting of nearly one thousand islands. It covers a land mass of . The capital, Honiara, is located on the island of Guadalcanal...
)
subgenus Carpolepis
- M. elegans (New Caledonia)
- M. laurifolia (New Caledonia)
- M. tardiflora (New Caledonia)