Agathis

Agathis, commonly known as kauri or dammara, is a genus of 22 species of evergreen tree. The genus is part of the ancient conifer family Araucariaceae, a group once widespread during the Jurassic and Cretaceous periods, but now largely restricted to the Southern Hemisphere except for a number of extant Malesian Agathis.[1][2]

Agathis
Temporal range:
Paleocene to recent
Te Matua Ngahere, an Agathis australis (New Zealand kauri)
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnosperms
Division: Pinophyta
Class: Pinopsida
Order: Araucariales
Family: Araucariaceae
Genus: Agathis
Salisb., 1807
Distribution of Agathis species
Synonyms[1]
  • Dammara (Rumph., 1741) Lam., 1786 ex Link, 1822
  • Salisburyodendron A.V.Bobrov & Melikyan

Description

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 circular 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

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

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]

Species list

Accepted species[1]
ImageScientific nameCommon NameDistribution
Agathis atropurpureablack kauri, blue kauriQueensland, Australia
Agathis australiskauri, New Zealand kauriNorth Island, New Zealand
Agathis borneensiswestern Malesia, Borneo
Agathis dammaraPhilippines, Sulawesi, Maluku Islands
Agathis flavescensPeninsular Malaysia
Agathis jurassica
Agathis kinabaluensisBorneo
Agathis labillardieriNew Guinea
Agathis lanceolataNew Caledonia
Agathis lenticulaBorneo
Agathis macrophylla (syn. A. vitiensis)Pacific kauri, dakuaFiji, Vanuatu, Solomon Islands
Agathis microstachyabull kauriQueensland, Australia
Agathis montanaNew Caledonia
Agathis mooreiwhite kauriNew Caledonia
Agathis orbiculaBorneo
Agathis ovataNew Caledonia
Agathis robustaQueensland kauriQueensland, Australia; New Guinea
Agathis silbaeVanuatu
Agathis spathulataNew Guinea kauriPapua New Guinea
Agathis zamuneraePatagonia, South America Argentina
Formerly included[1]

Moved to Nageia

  1. Agathis motleyi - Nageia motleyi
  2. Agathis veitchii - Nageia nagi

References

  1. Kew World Checklist of Selected Plant Families
  2. de Laubenfels, David J. 1988. Coniferales. P. 337–453 in Flora Malesiana, Series I, Vol. 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.
  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. ISSN 0002-9122. PMID 30074620. S2CID 51908977.
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