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"Pandanus julianettii" fruit cluster
Pandanus julianettii fruit cluster
Scientific classification
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Pandanales
Family: Pandanaceae
Genus: Pandanus
Subgenus: Lophostigma
Section: Karuka
Subsection: Karuka
P. julianettii
Binomial name
Pandanus julianettii
Karuka nuts (kernels)
Nutritional value per 100 g
Energy 2,259–2,929 kJ (540–700 kcal)
28-33.5 g
Sugars 5 g
Dietary fiber 9.2-25 g
35.6-47 g
Saturated 18 g
Trans 0
11.9-18 g
Tryptophan 102-136 mg
Threonine 435-482 mg
Isoleucine 503-555 mg
Leucine 904-993 mg
Lysine 426-526 mg
Methionine 272-279 mg
Cystine 204-234 mg
Phenylalanine 571-613 mg
Tyrosine 408-438 mg
Valine 745-832 mg
Arginine 1238-1329 mg
Histidine 293-336 mg
Alanine 585-642 mg
Aspartic acid 1064-1197 mg
Glutamic acid 2285-2453 mg
Glycine 638-701 mg
Proline 530-613 mg
Serine 545-584 mg
Vitamins Quantity%DV
Vitamin A 2 IU
Vitamin C
6.40 mg
Vitamin E
0.46 mg
Minerals Quantity%DV
97-460 mg
419 mg
220-360 mg
300.22 mg
71.21 mg
Other constituentsQuantity
Cholesterol 0
Percentages are roughly approximated using US recommendations for adults.
Source: [3] [2]
Karuka core (mesocarp)
Nutritional value per 100 g
Dietary fiber 5.3 g
0.43 g
8.5 g
Threonine 289 mg
Isoleucine 281 mg
Leucine 485 mg
Lysine 196 mg
Methionine 170 mg
Phenylalanine 315 mg
Tyrosine 323 mg
Valine 340 mg
Arginine 255 mg
Histidine 162 mg
Alanine 391 mg
Aspartic acid 672 mg
Glutamic acid 748 mg
Glycine 459 mg
Proline 196 mg
Serine 315 mg
Minerals Quantity%DV
120 mg
140 mg
Other constituentsQuantity
Cholesterol 0
Percentages are roughly approximated using US recommendations for adults.
Source: [3] [2]

Pandanus julianettii, also called karuka, karuka nut, or Pandanus nut, is a species of tree in the family Pandanaceae and an important regional food crop. [4] The nuts are more nutritious than coconuts, [2] and are so popular that villagers in the New Guinea Highlands will move their entire households closer to trees for the harvest season. [5] [6]



The specific epithet "julianettii" honors naturalist Amedeo Giulianetti, who found the original type specimens. [1]

Karuka is a loanword from Tok Pisin. [7] [8] Sometimes the tree is called 'karuga' [9] [10] [11] or 'karuka nut pandanus'. [12] The term 'karuka' can apply to both Pandanus julianettii and P. brosimos , though the latter is usually called 'wild karuka'. [5] Both species, as well as P. dubius , can be called 'pandanus nut'. [5] In addition to P. brosimos, 'wild karuka' can also refer to P. antaresensis , [12] P. iwen , and P. limbatus , but nuts from these trees are a much smaller part of the local diet. [5] In contexts where multiple karuka species are discussed, P. julianettii is sometimes termed 'planted karuka'. [12] P. julianettii, P. iwen, and P. brosimos are also in the subsection named Karuka , which is in the monotypic section also named Karuka . [13]

In New Guinea it goes by different names among each of the Papuan peoples. [4] In the Ankave language it is xweebo. [4] It is yase in the Baruya language. [4] The Huli language word is anga, [14] and it is also anga in the Duna language. [3] [4] [15] In Kewa language it is aga, [3] [4] [11] but it is unclear which dialect(s). In the Kewa pandanus language it is rumala agaa. [11] [16] The Kalam language term, in both standard and pandanus languages, is alŋaw. [17] [18] The plant is called ama in the Wiru language. [3] [4] In the Pole language it's called maisene. [3] [4] It goes by ank in Angal language, [3] [4] and aenk in the Wola dialect. [10] The Imbongu language word is amo. [4] [3] [16]

The plant also has many names on the other half of the island. In Indonesian it is called pandan kelapa (lit. coconut pandan) and kelapa hutan (forest coconut), [19] but the latter can also refer to P. brosimos and P. iwen. [20] The Dani people call it tuke. [19] [20] The Lani people call it woromo, [19] but this might be a separate species in the complex.


The species was originally described by Ugolino Martelli from only a few drupes in the collections of the Royal Botanic Gardens, Kew [1] He was hesitant to describe it as a new species from only that, but the characteristics were so salient he published his description. [1]

The tree is dioecious (individual plants either have male flowers of female ones), [4] with male trees uncommon compared to females. [3] It reaches 10–30 metres (33–98 ft) in height, with a grey trunk [2] of 30 centimetres (12 inches) in diameter and supported by buttress roots. [4] The trunk has white mottling and is generally smooth with occasional warts or small knobs as well as rings of leaf scars. [10] Inside the trunk is pithy and lacking cambium. [10] The top of the tree sometimes branches, producing three or four crowns of leaves. [3] Each crown will produce a single cluster of nuts, typically once every other season. [3] Production is affected by the seasonality of local rainfall. [5]

Leaves spiral up the trunk in opposite pairs. [3] [4] The large leathery leaves are 3–4 metres (9.8–13.1 ft) long [3] and 8–12 centimetres (3.1–4.7 in) wide. [4] The apex of the leaf is attenuate and doubly-pleated, with prickles pointing up at the tip [4] and along the margins and midrib. [2] The leaves are dark green on top and dull cyan underneath. [10]

The inflorescence on male trees is a densely-branched spadix with a dozen long spikes, each containing many staminate phalanges. [4] In each phalange is a column 3 mm long topped by up to 9 subsessile anthers. [4] The male flowers are white, [3] and the whole male flowering organ may be up to 2 metres (6 ft 7 in) long. [10]

The pollen has a psilate exine (unornamented outer wall) 0.8 μm thick. [21] The ornamentation is granular between echinae (short spines). [21] The ulcerate aperture is 3 μm in diameter. [21] Pollen grains measure an average of 30 × 14.5 μm in size. [21]

On female trees, the inflorescence is a single ellipsoid or ovoid syncarp, or fruiting head, with off-white bracts. [4] Female flowers can produce fruit without pollination, [2] and are typically the only trees cultivated. [10] The tree stops making leaves when new fruit is growing. [3] The syncarp has up to a thousand densely-packed single-celled carpels that later turn into drupes. [4] [3]

The clavate, pentagonal drupes measure up to 12 cm long and have a sharpened base, [1] but typically are 9×1.5 cm, [4] and are a pale blue-green color. [10] Each cluster contains about 1000 nuts. [3] The endocarp is bony and thin, [4]  cm long, with rounded edges about 1½ cm wide. [1] The seed-bearing locule is around 4 cm long. [1] The core of the mature head (mesocarp) has an appearance like honeycomb and is spongy [4] and pink. [3] The top of the mesocarp is fibrous, from 3 cm long and up. [1] Though Martelli did not have a complete syncarp, he knew the cluster of fruit must be large, estimating at least 30 cm in diameter. [1] He was correct, as the fruiting cluster is typically 15 to 30 cm in diameter. [3] A mature head and stalk weigh up to 16 kg, [4] but average 6 kg. [3]

It most closely resembles P. utilissimus , which is found the Philippines. [1] People also harvest and eat nuts of P. antaresensis, P. brosimos, P. dubius, P. iwen, and P. limbatus, and P. odoratissima [5]


There are up to 45 cultivated varieties of karuka, [10] many with different kernel shapes. [3] There are likely many more, as some cultivars are known only to a small number of people in a single settlement. [10] 'Tabuna' and 'Henga' are some of the most important cultivars. [2] 'Tabuna' is popular because it is high-yielding, tastes good, and has no taboos on who/what can eat it and how/if it is cooked. [2] At least two varieties are edible raw. [3]

Named varieties include: [2] [10]

It is possible a cultivar is listed more than once under different names, as Papua New Guinea has a very high linguistic diversity.

Benjamin Clemens Stone posits that P. julianettii and P. brosimos are a single species with many varieties, but does not support this point. [7] However, Simon G. Haberle notes that the pollen of the two trees are indistinguishable by light microscopy. [21] P. iwen may also be part of the species complex. [13]


Giulianetti's type specimens were collected from Vanapa, British New Guinea [1] (now southern Papua New Guinea). The tree can be found cultivated or wild on New Guinea, both in PNG and Papua province. [4] [3] Wild trees are found on the Huon Peninsula and in the highlands of New Guinea's central cordillera. [4] [5] In Papua New Guinea, the tree is most commonly grown in Southern Highlands, Western Highlands, Eastern Highlands, Enga, and Chimbu Provinces, and it is found in all provinces on the mainland except East Sepik. [12] It grows in montane forests [7] between 1,300 and 3,300 m in elevation in areas that get 2-5 m mean annual precipitation. [4] [5] It grows in both dry and wet soils, [4] [5] but prefers good soil fertility. [3] Trees will grow in clumped groups of 5 to 10 individuals per hectare. [5]


Karuka produces fruit around February, with an occasional secondary season in July. [3] Typically each branch will only flower every other year. [3] The natural pollination syndrome is unknown, but the flowers can be pollinated by humans. [5] Seed dispersal is by humans, birds, and other animals. [5] A fallen syncarp will disintegrate completely in about 3 days in the forest. [2]

Fungal pests of karuka include leaf spot, diffuse leaf spot, black leaf mould ( Lembosia pandani ), sooty mold ( Meliola juttingii ), and fungus on seeds ( Macrophoma pandani ). [3] The leaf moulds do not do much damage. [3] The sooty mould seems to grow on insect frass. [3] The black leaf mold only affects some varieties. [3]

The bacteria Pectobacterium carotovorum subsp. carotovorum can also cause bacterial soft rot and necrosis on the leaves, but causes more severe damage to the related species Pandanus conoideus . [9]

Longhorn grasshoppers (Tettigoniidae) are serious insect pests. [3] Segestes gracilis and Segestidea montana eat the leaves and can sometimes kill trees. [3] Growers will stuff leaves and grass in between the leaves of the crown to keep insects out. [3] An unknown species of black grub will burrow into the cluster and eat the spongy core, causing the nuts to turn black and the whole bunch to fall off the tree. [3] Woodboring beetles sometimes attack the prop root of the tree. [3]

Possums also eat the nuts, [3] as do rodents such as squirrel-toothed rats (Anisomys imitator), eastern white-eared giant rats (Hyomys goliath), Rothschild's woolly rats (Mallomys rothschildi), and giant naked-tailed rats (Uromys anak). [10] Growers will put platforms or other obstacles on the trunks of trees to keep the pests out. [3] [10]

Harvested nuts are often beset by rats and cockroaches. [3] Hanging nuts in the smoky areas above fires can prevent this, but after a while the taste of the nuts is affected. [3]

Use by humans

On New Guinea karuka is cultivated crop, [4] and has been used as a major food source since nearly 31,000 years ago in the Pleistocene. [8] In PNG nearly 2 million people (almost half the rural population) live in regions where karuka is commonly eaten. [12] There is high demand for it in the New Guinea Highlands: Entire households (including pigs, who are sometimes fed the fruits [2] ) will move from the valleys to higher elevations at harvest time, [5] often for several weeks. [6] Each household will average 12 to 176 trees. [6]

Trade in karuka is small-scale and not commercial. [5] Local marketplaces typically will have 12 to 50 fruits for sale. [6] With some coordination between state agencies and private sector, karuka could have export market access. [12] The crop has a medium potential for large-scale sustainable commercialization in the region, but care must be taken in the sensitive local environments to expanded agriculture. [5] Diets of tree owners could also be negatively influenced by rapid commercialization. [5]

The endosperm, a white kernel, is eaten raw, roasted, smoked, [4] or mumued. [3] Nuts that aren't immediately eaten are typically sun-dried for storage. [3] The karuka kernels have a sweet, coconut taste, [4] [10] [19] or savory and like walnuts. [20] Smoked or cooked karuka is either stored in the rafters or sold at local marketplaces. [4] The uncooked clusters can also be stored for months buried in waterlogged earth, [4] [3] [2] which possibly ferments it. [10] It is a regional staple food and one of the few plants in the area with a high protein content. [4] The spongy core of the multiple fruit cluster can also be cooked and eaten after the nuts are removed. [4] [3]

Oil extracted from the nuts

The high fat content means the nuts can be processed into an edible yellow oil. [19] Karuka contains 52.39% oleic acid, 44.90% palmitic acid, and 0.19% stearic acid. [20] The oil is a good source of Vitamin E (α-tocopherol 5.03 mg/100 g). [19] The color of the oil is from the carotenoids, which are at a concentration of 2.75 µg/g. [19] The antioxidant activity for the oil is fairly low, and it is higher in saturated than unsaturated fats. [19]

Some subjective reports indicate that children are healthier after karuka season, but there may also be increased incidence of tropical ulcers and pig-bel (caused by Clostridium perfringens ). [2] But the connections, if valid, are unclear.

Trunks and buttress roots are used for building. [4] The sheets of bark are used for house walls. [10] The leaves are used for bush shelters [4] and raincapes. [10] The leaves were the preferred building material for housing in Papua New Guinea before colonial contact. [22] The durable white spathe leaves on male inflorescences are used by the Wola people to wrap pearl shells. [10]

Karuka can be cultivated by cutting a mature branch and replanting it (vegetative propagation). [3] Suckers can also be replanted. [3] Nurseries also plant seeds directly. [3] New nuts will grow when a tree is at least five or six years old, and can keep producing for up to fifty years. [3] [2] The tree can tolerate temperatues down to 3°C for extended periods and 0°C for short periods. [15] The USDA hardiness is 10–12, and is hardy to zone 10 in the UK system. [23]

In Upper Karint near Pingirip, karukas are planted as boundary lines between garden plots. [3]

Pandanus languages

Ritual pandanus languages are known from multiple areas of Papua New Guinea. [11] In the Mount Giluwe area three separate language groups, Kewa, Melpa, and Mendi, use pandanus language, [11] as does Imbongu, [16] , Huli, [14] and Kalam. [17] The grammar and vocabulary of pandanus language is based on the mother tongue, but a restricted and consolidated form, especially for names of living organisms. [11] The new vocabulary focuses on words involved with trips to harvest karuka nuts, and changes as words become known outside an area. [11] The language is spoken to control the magical properties of the higher elevations where the karuka grows, and to placate dangerous spirits like Kita-Menda (also called Giluwe yelkepo [16] ), the ritual keeper of the wild dogs. [11] All ages and genders are expected to know the ritual language before entering the taboo areas, but outsiders who do not know the language may be allowed to speak Tok Pisin instead. [11] The taboo areas are typically marked with signs, usually Cordyline or other leaves tied to sticks. [11] Pandanus language is not spoken outside the designated areas for fear of mountain spirits hearing it and coming down to investigate. [11]

As Tok Pisin has become more widely spoken in the area, pandanus languages have been spoken less. [16] Newer generations also seem to be less afraid of the deep forest, and do not see much need for the protective talk. [16] The Kewa and Imbongu pandanus languages are already thought to be dying out. [16]

In culture

In PNG's Central Province Premier Rugby League the team for Goilala District is called the Karukas. [24]


  1. 1 2 3 4 5 6 7 8 9 10 11 12 Martelli, Ugolino (December 1907). Martelli, Ugolino, ed. "Pandanus Nuove Specie Descritte Manipolo II". Webbia, Raccolta di Scritti Botanici (in Italian). 2: 433. doi:10.1080/00837792.1907.10803460. hdl:2027/mdp.39015038487925. ISSN   2169-4060. OCLC   899525984.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Rose, C. J. (1982). Bourke, Richard Michael; Kesavan, V., eds. "Preliminary Observations on the Pandanus nut (Pandanus jiulianettii Martelli)". Proceedings of the Second Papua New Guinea Food Crops Conference. 1: 160–167. OCLC   17294235.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 French, Bruce R. (1982). Growing food in the Southern Highlands Province of Papua New Guinea (PDF). AFTSEMU (Agricultural Field Trials, Surveys, Evaluation and Monitoring Unit) of the World Bank funded project in the Southern Highlands of Papua New Guinea. pp. 64–71. Retrieved 20 September 2018.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Lim, Tong Kwee (2012). "Pandanus julianettii". Edible Medicinal And Non-Medicinal Plants. 4. Springer. pp. 128–130. doi:10.1007/978-94-007-4053-2_17. ISBN   978-94-007-4053-2. OCLC   822591349.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Bourke, Richard Michael. "Edible indigenous nuts in Papua New Guinea" (PDF). In Stevens, M.L.; Bourke, Richard Michael; Evans, Barry R. South Pacific Indigenous Nuts. Proceedings of a workshop held from 31 October to 4 November 1994 at Le Lagon Resort, Port Vila, Vanuatu. Australian Centre for International Agricultural Research Proceedings. 69. Canberra: Australian Centre for International Agricultural Research. pp. 45–55. ISBN   1 86320 485 7. OCLC   38390455 . Retrieved 27 September 2018.
  6. 1 2 3 4 Bourke, Richard Michael (May 1988). Taim hangre: variation in subsistence food supply in the Papua New Guinea highlands (PDF). Australian National University. OCLC   224338489 . Retrieved 27 September 2018.
  7. 1 2 3 Stone, Benjamin C. (1982). "7 New Guinea Pandanaceae: first approach to ecology and biogeography". In Gressitt, J. L. Biogeography and Ecology of New Guinea. Monographiae Biologicae. 1. Dordrecht: Springer. pp. 401–436. doi:10.1007/978-94-009-8632-9_17. ISBN   978-94-009-8632-9. OCLC   5679030487.
  8. 1 2 Denham, Tim (July 2007). "Exploiting diversity: plant exploitation and occupation in the interior of New Guinea during the Pleistocene". Archaeology in Oceania. 42 (2): 41–48. doi:10.1002/j.1834-4453.2007.tb00015.x. ISSN   1834-4453. OCLC   696476493.
  9. 1 2 Tomlinson, D. L. (January 1988). "A Leaf and Fruit Disease of Pandanus conoideus caused by Erwinia carotovora subsp. carotovora in Papua New Guinea". Journal of Phytopathology. 121 (1): 19–25. doi:10.1111/j.1439-0434.1988.tb00948.x. ISSN   0931-1785. OCLC   4660013776.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Stilltoe, Paul (1983). Roots of the Earth: Crops in the Highlands of Papua New Guinea. Manchester, UK: Manchester university Press. ISBN   978-0-7190-0874-0. LCCN   82-62247. OCLC   9556314.
  11. 1 2 3 4 5 6 7 8 9 10 11 Franklin, Karl J. (September 1972). "A Ritual Pandanus Language of New Guinea". Oceania. 43 (1): 66–76. doi:10.1002/j.1834-4461.1972.tb01197.x. OCLC   883021898.
  12. 1 2 3 4 5 6 Quartermain, Alan R.; Tomi, Barbara, eds. (2010). Fruits and Nuts: Research and Development Issues in Papua New Guinea Papers presented at the Fruits and Nuts Workshop held at the IATP Farmer Training Centre, University of Natural Resource and Environment (formerly University of Vudal) from 11–13 October 2005 (PDF). Workshop Proceedings. 9. Lae, Papua New Guinea: National Agricultural Research Institute. Retrieved 2 October 2018.
  13. 1 2 Stone, Benjamin Clemens (July 1984). "Pandanus from Ok Tedi region, Papua New Guinea, collected by Debra Donoghue". Economic Botany. 38 (3): 304–313. doi:10.1007/BF02859008. ISSN   1874-9364. OCLC   7025621147.
  14. 1 2 Goldman, Laurence (1983). "Talking about talk". Talk Never Dies: The Language of Huli Disputes. London and New York: Tavistock Publications. pp. 254–257. ISBN   978-0422782104. OCLC   993340993.
  15. 1 2 "Pandanus julianettii" (HTML). Ecocrop. Food and Agriculture Organization of the UN. 1993–2007. Retrieved 26 October 2018.
  16. 1 2 3 4 5 6 7 Franklin, Karl J.; Stefaniw, Roman (1992). "The 'Pandanus Languages' of the Southern Highlands Province, Papua New Guinea - a further report" (PDF). In Dutton, Tom. Culture change, language change - case studies from Melanesia. Pacific Linguistics. C-120. Canberra: Department of Linguistics Research School of Pacific Studies THE AUSTRALIAN NATIONAL UNIVERSITY. pp. 1–6. doi:10.15144/PL-C120.1. ISBN   978-0858834118. ISSN   0078-7558. OCLC   260177442 . Retrieved 25 October 2018.
  17. 1 2 3 Majnep, Ian Saem; Bulmer, Ralph (1977). Birds of my Kalam Country[Mn̄mon Yad Kalam Yakt]. illustrations by Christopher Healey. New Zealand: Aukland University Press. pp. 53, 150, 152. ISBN   9780196479538. OCLC   251862814.
  18. Pawley, Andrew (1992). "Kalam Pandanus Language: An Old New Guinea Experiment in Language Engineering". In Dutton, Tom E.; Ross, Malcolm; Tryon, Darrell. The Language Game: Papers in Memory of Donald C. Laycock. Pacific Linguistics Series C. 110. Memory of Donald C. Laycock. Canberra: Department of Linguistics, Research School of Pacific Studies, Australian National University. pp. 313–334. ISBN   08588334006 Check |isbn= value: length (help). ISSN   0078-7558. OCLC   222981840.
  19. 1 2 3 4 5 6 7 8 Zebua, Lisye Iriana; Purnamasari, Vita (26 January 2018). "Oil of Pandan Kelapa Hutan (Pandanus jiulianettii Martelli): Physicochemical Properties, Total Phenols, Total Carotene, Vitamin E and Antioxidant Activity" (PDF). Jurnal Biologi Udayana. 21 (2): 71–77. doi:10.24843/JBIOUNUD.2017.vol21.i02.p05. ISSN   2599-2856. OCLC   7347063503 . Retrieved 20 October 2018.
  20. 1 2 3 4 Purwanto, Y.; Munawaroh, Esti (2010). "Etnobotani Jenis-Jenis Pandanaceae Sebagai Bahan Pangan di Indonesia" [Ethnobotany Types of Pandanaceae as Foodstuffs in Indonesia](PDF). Berkala Penelitian Hayati (in Indonesian). 5A: 97–108. doi:10.5072/FK2/Z6P0OQ. ISSN   2337-389X. OCLC   981032990 . Retrieved 25 October 2018.
  21. 1 2 3 4 5 Haberle, Simon G. (November 1995). "Identification of cultivated Pandanus and Colocasia in pollen records and the implications for the study of early agriculture in New Guinea". Vegetation History and Archaeobotany. 4 (4): 195–210. doi:10.1007/BF00235751. ISSN   1617-6278. OCLC   192800152.
  22. Halvaksz, Jamon (December 2010). "The Photographic Assemblage: Duration, History and Photography in Papua New Guinea" (PDF). History and Anthropology. 21 (4): 411–429. doi:10.1080/02757206.2010.521556. ISSN   0275-7206. OCLC   683378311 . Retrieved 12 October 2018.
  23. "Pandanus julianettii - Martelli" (HTML). Plants for a Future. 1996–2012. Retrieved 26 October 2018.
  24. Pangkatana, John (September 21, 2018). "Karukas to be put to acid test in Central playoffs The Goilala Karukas are set to move into high gear" (HTML). Post Courier Online. Retrieved 4 October 2018.