''Metrosideros bartlettii'', also known as Bartlett's rātā, Cape Reinga white rātā or in

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

as rātā moehau, is one of twelve ''

Metrosideros ''Metrosideros'' is a genus of approximately 60 trees, shrubs, and vines mostly found in the Pacific region in the family Myrtaceae. Most of the tree forms are small, but some are exceptionally large, the New Zealand species in particular. The ...

'' species endemic to

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

and is notable for its extreme rarity and its white flowers, somewhat uncommon in that genus of red-flowered trees and plants. Its natural range is in the far north of the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-larges ...

at Te Paki, in three patches of dense native forest near

Spirits Bay Spirits Bay, officially named Piwhane / Spirits Bay, is a remote bay at the northern end of the Aupouri Peninsula, which forms the northern tip of New Zealand's North Island. It lies between Cape Reinga / Te Rerenga Wairua in the west and Ngataea ...

(34° S) that escaped destruction by fire, namely Radar Bush, Kohuronaki Bush, and Unuwhao Bush. Only 13 adult trees are known to exist in the wild (down from 34 in 1992) and most of these are either ill or dying. The lack of fossil evidence elsewhere suggests that the tree may always have been restricted to the North Cape area, which was an island until it was connected to the mainland by the sandspit that constitutes Ninety Mile Beach.

Description

''Metrosideros bartlettii'' was discovered by John Bartlett, a schoolteacher from

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The most populous urban area in the country and the fifth largest city in Oceania, Auckland has an urban population of about I ...

, in 1975. He found an unusual tree growing in Radar Bush, 9.5 km south-east of Cape Reinga. Almost ten years passed before the flowers were collected, making possible a scientific description of the tree. Bartlett's rātā grows to a height of up to thirty metres, usually beginning life as a hemi-epiphyte on taraire ('' Beilschmiedia tarairi''), puriri (''

Vitex lucens ''Vitex lucens'', or pūriri, is an evergreen tree endemic to New Zealand. History Pūriri was first collected (by Europeans) at Tolaga Bay by Banks and Solander during Cook's first visit in 1769. The plant was excellently described by Soland ...

''), rewarewa (''

Knightia excelsa ''Knightia excelsa'', commonly called rewarewa (from Māori), is an evergreen tree endemic to the low elevation and valley forests of New Zealand's North Island and Marlborough Sounds (41° S) and the type species for the genus '' Knightia''. ...

'') or tree ferns ('' Cyathea'' spp.). Occasionally, the tree is found growing on the ground on rock outcrops and rocky cliffs. The tree bears white flowers made up of a mass of

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the fila ...

s in November or December. Seed ripens in March or April. The trunk is up to 1.5 m in diameter. Bartlett's rātā resembles northern rātā (''

Metrosideros robusta ''Metrosideros robusta'', the northern rātā, is a forest tree endemic to New Zealand. It grows up to 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 d ...

'') but can be distinguished by the small white flowers and by the leaves, which taper to a point at the tip, while those of northern rātā are notched at the tip. Also distinctive is the white or whitish-grey bark that peels easily into soft flakes, which it is thought may offer resistance to fire damage. This may have been a key factor in the tree's precarious survival in an area prone to forest fire.

Conservation

Although the plant is in cultivation, the majority of cultivated plants come from one tree. Only 13 adult Bartlett's rātā are known to exist in the wild, and most of these are growing on privately owned land. Many of the specimens are isolated from other trees with the result that there is minimal transfer of pollen and few seeds are set. Analyses of the DNA have shown that there is very little genetic variation. The species is also vulnerable to browsing animals, and at risk of destruction by fire or by changes in the land management practices of the landowners. Iwi

Ngāti Kurī Ngāti Kurī is a Māori iwi from Northland, New Zealand. The iwi is one of the five Muriwhenua iwi of the far north of the North Island. Ngāti Kurī trace their whakapapa (ancestry) back to Pōhurihanga, the captain of the waka (canoe) Kurah ...

and the

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment ...

have been working to restore tree numbers, including 360 trees planted into Radar Bush and Kohuronaki Bush. Work is also going into planting at Unuwhao Bush (the tree's current stronghold), as well as establishing new sites in the Far North utilising seedlings from all three remaining pockets of established trees, to maximise the remaining genetic diversity.

Cultivation

Bartlett's rātā grows readily from fresh seed, and prefers sunny sites with fertile, well drained soil. It can also be propagated from hardwood cuttings, although these may be very slow to take root. Plants in cultivation in New Zealand are relatively hardy in a range of conditions, and have shown tolerance of mild frosts, which are unknown in the natural habitat.

Notes

References

* * * Simpson, P., 2005. ''Pōhutukawa & Rātā: New Zealand's Iron-Hearted Trees''. Wellington: Te Papa Press. *

External links