Karaka (tree)

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Karaka
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Mature tree showing trunk and foliage.
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Celastrales
Family: Corynocarpaceae
Genus: Corynocarpus
Species: C. laevigatus
Binomial name
Corynocarpus laevigatus

Karaka (Corynocarpus laevigatus) is an evergreen tree with large glossy leaves endemic to New Zealand, where it is widespread in mainly coastal situations, often forming a major component of coastal forest, although it is rarely a dominant tree. Sometimes Karaka occurs inland, usually the result of Māori plantings near former village sites.[1]

Distribution

Karaka is widespread in mainly coastal situations. The tree is endemic to New Zealand, where the original distribution is unclear because of widespread planting by Maori. The tree is common throughout the North and South Islands to Banks Peninsula (43°45′S)and Okarito (43°20′S), on the Three Kings Islands, on Raoul Island in the Kermadecs, and on the Chatham Islands. In the last two localities the presence of the tree is probably the result of Polynesian plantings. Most botanists accept it as native only in the northern half of the North Island.[2]

Description

File:Corynocarpuslaevigatus012.jpg
The orange fruit, produced in summer, contain highly poisonous kernels.
Karaka is a leafy canopy tree with erect or spreading branches. It grows to heights of up to 15 metres and has a stout trunk up to 1 metre in diameter. The thick, leathery leaves are dark green above and paler beneath, 50 to 200mm wide and 30 to 70 mm wide. The leaves are glossy. In winter and spring (August to November) it produces stout, erect panicles of tiny flowers with petioles 10-15 mm long. The individual flowers are 4 to 5 mm in diameter, greenish-cream to off-white or pale yellow. The fruit is an ellipsoid to ovoid drupe 25 to 46 mm long, with pale yellow to orange flesh, and the seed is a single kernel. The fruit ripens in summer and autumn (January to April).

Poisonous seeds

The pulp of the fruit is edible, although bitter, but the fresh kernels contain the lethal alkaloid poison karakin. Accounts from the 19th century record that extensive processing was used by Māori to convert the kernels to an edible form, and mention that if the processing was not done with the greatest care, poisoning would result with symptoms including violent convulsions and severe muscle spasms which could leave the limbs permanently fixed in contorted positions. Death resulted in a few cases.[3]

Cultivation

Karaka may be easily grown from fresh seed, but cuttings are very difficult to strike. Young plants are frost-tender and sensitive to cold. The tree will often naturalise in suitable habitats. It is common in cultivation and widely available for sale both in New Zealand and in suitable climates elsewhere. It is regarded as a serious pest species in Hawaii.

References

Notes

  1. The common name Karaka comes from the Māori language, and has become the Māori term for the colour orange, from the colour of the fruit. An alternative name, which is little used is New Zealand Laurel. In the Chatham Islands, it is called ‘Kopi’, its name in the Moriori language.
  2. New Zealand Plant Conservation Network
  3. Skey 1871:318
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mi:Karaka