''Agathis'', commonly known as kauri or dammara, is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of 22 species of

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

. The genus is part of the ancient

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ext ...

family Araucariaceae, a group once widespread during the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

and

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

periods, but now largely restricted to the Southern Hemisphere except for a number of

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

Malesian ''Agathis''.de Laubenfels, David J. 1988. Coniferales. P. 337–453 in Flora Malesiana, Series I, Vol. 10. Dordrecht: Kluwer Academic.

Description

Mature kauri trees have characteristically large trunks, with little or no branching below the crown. In contrast, young trees are normally

conical A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines c ...

in shape, forming a more rounded or irregularly shaped crown as they achieve maturity.Whitmore, T.C. 1977. ''A first look at Agathis''. Tropical Forestry Papers No. 11.

University of Oxford , mottoeng = The Lord is my light , established = , endowment = £6.1 billion (including colleges) (2019) , budget = £2.145 billion (2019–20) , chancellor ...

Commonwealth Forestry Institute The Department of Plant Sciences, at the University of Oxford, England, was a former Oxford department that researched plant and fungal biology. It was part of the university's Mathematical, Physical and Life Sciences Division. From 1 August 2 ...

. The

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...

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 A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

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 Linearity is the property of a mathematical relationship ('' function'') that can be graphically represented as a straight line. Linearity is closely related to '' proportionality''. Examples in physics include rectilinear motion, the 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 Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to ...

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

cones appear usually only on larger trees after

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

cones have appeared. The

female Female ( symbol: ♀) is the sex of an organism that produces the large non-motile ova (egg cells), the type of gamete (sex cell) that fuses with the male gamete during sexual reproduction. A female has larger gametes than a male. Fema ...

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

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sy ...

s of '' Agathiphaga'', some of the most primitive of all living moths.

Uses

Various species of kauri give diverse

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on nat ...

s such as kauri gum. The

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, w ...

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

guitar The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...

s and

ukulele The ukulele ( ; from haw, ukulele , approximately ), also called Uke, is a member of the lute family of instruments of Portuguese origin and popularized in Hawaii. It generally employs four nylon strings. The tone and volume of the instrumen ...

s due to its low

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...

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 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 ...

for wooden weapons, patu aruhe (fernroot beaters) and barkcloth beaters.

Evolutionary history

Within Araucariaceae, Agathis is more closely related to '' Wollemia'' than to ''

Araucaria ''Araucaria'' (; original pronunciation: .ɾawˈka. ɾja is a genus of evergreen coniferous trees in the family Araucariaceae. There are 20 extant species in New Caledonia (where 14 species are endemic, see New Caledonian ''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 The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pala ...

, approximately 64.67–63.49 million years ago. ''Agathis''-like leaves are also known from the slightly older

Lefipán Formation The Lefipán Formation is a Maastrichtian to Danian, straddling the Cretaceous-Paleogene boundary, geologic formation of the Cañadón Asfalto Basin in Chubut Province, Patagonia, Argentina. The up to thick stratigraphic unit comprises mudston ...

of the same region, which date to the very end of the Cretaceous.

Species list

;Accepted species ;Formerly included Moved to '' Nageia'' # ''Agathis motleyi -

Nageia motleyi ''Nageia motleyi'' is a species of conifer in the family Podocarpaceae Podocarpaceae is a large family of mainly Southern Hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James ...

'' # ''Agathis veitchii - Nageia nagi''

Gallery

File:'Lord of the Forest' Tane Mahuta.jpg, Tāne Mahuta, an '' Agathis australis'' in Waipoua Forest, the largest tree in New Zealand by volume File:Te Matua Ngahere.jpg, Te Matua Ngahere, an ''A. australis'' in Waipoua Forest, the oldest (and 2nd largest) tree in New Zealand File:Yakas kauri tree trunk 2.jpg, Trunk of the Yakas kauri (7th largest) File:Agathis lanceolata.jpg, ''Agathis lanceolata'' File:Agathis ovata 2.jpg, ''Agathis ovata'' File:AgathisMacroCones.jpg, ''Agathis macrophylla'' File:Agathisrobusta.JPG, ''Agathis robusta'' File:Agathis borneensis - feuilles.JPG, ''Agathis borneensis'' File:KauriFruchtstand.jpg, '' Agathis australis'' male pollen cone File:KauriSamen.jpg, alt=Agathis australis chaff (seed is small and winged), '' Agathis australis'' seed File:Kauricone01.jpg, '' Agathis australis'' cone File:Agathis australis foliage and cones.jpg, '' Agathis australis'' leaves and cones

References

External links

Systematics of ''Agathis''

Kauri forest
in '' Te Ara: The Encyclopedia of New Zealand''
Threatened Conifers of the World
{{Taxonbar, from=Q216113 Conifer genera