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Agathis

From Wikipedia, the free encyclopedia
For the genus of wasps, see Agathis (wasp).
"Kauri" redirects here. For other uses, see Kauri (disambiguation).
Not to be confused with the eucalyptus species karri.

Agathis
Temporal range:
Paleocene to recent 64.67–0 Ma
Agathis robusta Eastern Australia
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Araucariales
Family: Araucariaceae
Genus: Agathis
Salisb. 1807
Type species
Agathis loranthifolia
Salisb. 1807
Distribution of Agathis species
Synonyms[1]
  • Dammara (Rumph., 1741) Lam., 1786 ex Link, 1822
  • Salisburyodendron A.V.Bobrov & Melikyan

Agathis, commonly known as kauri or dammara, is a genus of evergreen coniferous trees, native to Australasia and Southeast Asia. It is one of three extant genera in the family Araucariaceae, alongside Wollemia and Araucaria (being more closely related to the former).[1][2] Its leaves are much broader than most conifers. Kauri gum is commercially harvested from New Zealand kauri.

Description

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Bark of Agathis robusta at Melbourne Royal Botanic Gardens (leaves belong to another plant)

Mature kauri trees have characteristically large trunks, with little or no branching below the crown. In contrast, young trees are normally conical in shape, forming a more rounded or irregularly shaped crown as they achieve maturity.[3]

The bark is smooth and light grey to grey-brown, usually peeling into irregular flakes that become thicker on more mature trees. The branch structure is often horizontal or, when larger, ascending. The lowest branches often leave annular branch scars when they detach from the lower trunk.

The juvenile leaves in all species are larger than the adult, more or less acute, varying among the species from ovate to lanceolate. Adult leaves are opposite, elliptical to linear, very leathery and quite thick. Young leaves are often a coppery-red, contrasting markedly with the usually green or glaucous-green foliage of the previous season.

The male pollen cones appear usually only on larger trees after seed cones have appeared. The female seed cones usually develop on short lateral branchlets, maturing after two years. They are normally oval or globe shaped.

Seeds of some species are attacked by the caterpillars of Agathiphaga, some of the most primitive of all living moths.

Uses

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Kauri logs and loggers near Piha

Various species of kauri give diverse resins such as kauri gum. The timber is generally straight-grained and of fine quality with an exceptional strength-to-weight ratio and rot resistance, making it ideal for yacht hull construction. The wood is commonly used in the manufacture of guitars and ukuleles due to its low density and relatively low price of production. It is also used for some Go boards (goban). The uses of the New Zealand species (A. australis) included shipbuilding, house construction, wood panelling, furniture making, mine braces, and railway sleepers. Due to the hard resin of the wood, it was the traditionally preferred material used by Māori for wooden weapons, patu aruhe (fernroot beaters) and barkcloth beaters.[4]

Evolutionary history

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Within Araucariaceae, Agathis is more closely related to Wollemia than to Araucaria. The oldest fossils currently confidently assignable to Agathis are those of Agathis immortalis from the Salamanca Formation of Patagonia, which dates to the Paleocene, approximately 64.67–63.49 million years ago. Agathis-like leaves are also known from the slightly older Lefipán Formation of the same region, which date to the very end of the Cretaceous.[5] Other fossils of the genus are known from the Eocene of Patagonia, the Late Paleocene-Miocene of southern Australia, and the Oligocene-Miocene of New Zealand.[6]

Species list

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Phylogeny of Agathis[7]
Araucariaceae
Rostrata

A. australis
(Don) Lindley

Agathis

A. atropurpurea
Hyland

A. microstachya
Bailey & White

A. dammara
(Lamb.) Richard & Richard

A. robusta
(Moore ex von Mueller) Bailey

A. vitiensis
(Seemann) Bentham & Hooker
ex Drake

A. macrophylla
(Lindley 1851) Masters

A. silbae
de Laubenfels

A. corbassonii
de Laubenfels

A. lanceolata
Lindl. ex Warburg

A. ovata
(Moore ex Vieillard) Warburg

A. moorei
(Lindley) Masters

A. montana
de Laubenfels

Accepted species[1]
Image Scientific name Common Name Distribution
Agathis atropurpurea black kauri, blue kauri Queensland, Australia
Agathis australis New Zealand kauri North Island, New Zealand
Agathis borneensis Borneo kauri western Malesia, Borneo
Agathis dammara Sulawesi kauri Philippines, Sulawesi, Maluku Islands
  Agathis flavescens Tahan Agathis Peninsular Malaysia
Agathis kinabaluensis Kinabalu kauri Borneo
  Agathis labillardieri New Guinea kauri New Guinea
Agathis lanceolata Koghi kauri New Caledonia
  Agathis lenticula Sabah kauri Borneo
Agathis macrophylla (syn. A. vitiensis) Pacific kauri, dakua Fiji, Vanuatu, Solomon Islands
Agathis microstachya bull kauri Queensland, Australia
  Agathis montana New Caledonia
Agathis moorei white kauri New Caledonia
  Agathis orbicula Sarawak kauri Borneo
Agathis ovata Scrub kauri New Caledonia
Agathis robusta Queensland kauri Queensland, Australia; Papua New Guinea
  Agathis robusta subsp. robusta Queensland and Papua New Guinea
  Agathis robusta subsp. nesophila New Guinea kauri Papua New Guinea
  Agathis silbae Vanuatu
  Agathis zamunerae Patagonia, South America Argentina
Formerly included[1]

Moved to Nageia

The placement of the fossil species "Agathis" jurassica from the Late Jurassic of Australia in this genus is doubtful.[8]

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References

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  1. ^ a b c d Kew World Checklist of Selected Plant Families
  2. ^ de Laubenfels, David J. 1988. Coniferales. P. 337–453 in Flora Malesiana, Series I, Volume 10. Dordrecht: Kluwer Academic.
  3. ^ Whitmore, T.C. 1977. A first look at Agathis. Tropical Forestry Papers No. 11. University of Oxford Commonwealth Forestry Institute.
  4. ^ Neich, Roger (1996). "New Zealand Maori Barkcloth and Barkcloth Beaters". Records of the Auckland Institute and Museum. 33: 111–158. ISSN 0067-0464. JSTOR 42906461. Wikidata Q58677501.
  5. ^ Escapa, Ignacio H.; Iglesias, Ari; Wilf, Peter; Catalano, Santiago A.; Caraballo-Ortiz, Marcos A.; Rubén Cúneo, N. (August 2018). "Agathis trees of Patagonia's Cretaceous-Paleogene death landscapes and their evolutionary significance". American Journal of Botany. 105 (8): 1345–1368. doi:10.1002/ajb2.1127. hdl:11336/87592. ISSN 0002-9122. PMID 30074620. S2CID 51908977.
  6. ^ Wilf, Peter; Escapa, Ignacio H.; Cúneo, N. Rubén; Kooyman, Robert M.; Johnson, Kirk R.; Iglesias, Ari (January 2014). "First South American Agathis (Araucariaceae), Eocene of Patagonia". American Journal of Botany. 101 (1): 156–179. doi:10.3732/ajb.1300327. hdl:11336/27660. ISSN 0002-9122. PMID 24418576.
  7. ^ Stull, Gregory W.; Qu, Xiao-Jian; Parins-Fukuchi, Caroline; Yang, Ying-Ying; Yang, Jun-Bo; Yang, Zhi-Yun; Hu, Yi; Ma, Hong; Soltis, Pamela S.; Soltis, Douglas E.; Li, De-Zhu; Smith, Stephen A.; Yi, Ting-Shuang (19 July 2021). "Gene duplications and genomic conflict underlie major pulses of phenotypic evolution in gymnosperms" (PDF). Nature Plants. 7 (8): 1015–1025. bioRxiv 10.1101/2021.03.13.435279. doi:10.1038/s41477-021-00964-4. PMID 34282286. S2CID 232282918 – via bioarchiv.org.
    supplementary data:
    Stull, Gregory W. (29 June 2021). Gene duplications and genomic conflict underlie major pulses of phenotypic evolution in gymnosperms (supplementary data). doi:10.6084/m9.figshare.14547354.v1 – via Figshare.com.
  8. ^ Hill, Robert S. & Brodribb, Tim J. (1999). "Southern conifers in time and space". Australian Journal of Botany. 47 (5): 639–696. doi:10.1071/BT98093. cited in Dettmann, Mary E. & Clifford, H. Trevor (2005). "Biogeography of Araucariaceae" (PDF). In Dargavel, John (ed.). Araucarian Forests. Kingston, Australia: Australian Forest History Society. pp. 1–9. ISBN 978-0-9757906-1-8. Archived from the original on 2018-12-03. Retrieved 2021-05-17.{{cite book}}: CS1 maint: bot: original URL status unknown (link)
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