Araucariaceae

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Araucariaceae
Temporal range: Early Jurassic–Present (possible Late Triassic records)
Araucaria angustifolia at Minas Gerais
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Araucariales
Family: Araucariaceae
Henkel & W. Hochstetter
Type genus
Araucaria
Genera

Araucariaceae – also known as araucarians – is a family of coniferous trees, with three living genera, Araucaria, Agathis, and Wollemia. While the family was distributed globally during the Jurassic and Cretaceous periods, they are now largely confined to the Southern Hemisphere, except for a few species of Agathis in Southeast Asia.[1]

Description[edit]

Tāne Mahuta ("Lord of the Forest"), a massive Agathis australis tree from New Zealand

Members of Araucariaceae are typically extremely tall evergreen trees,[2] reaching heights of 60 m (200 ft) or more.[3] They can also grow very large stem diameters; a New Zealand kauri tree (Agathis australis) named Tāne Mahuta ("The Lord of the Forest") has been measured at 45.2 m (148 ft) tall with a diameter at breast height of 491 cm (16.11 ft). Its total wood volume is calculated to be 516.7 m3 (18,250 cu ft),[4] making it the third-largest conifer after Sequoia and Sequoiadendron (both from the Cupressaceae subfamily Sequoioideae).[2]

The trunks are columnar and have relatively large piths with resinous cortices.[5] The branching is usually horizontal and tiered, arising regularly in whorls of three to seven branches or alternating in widely separated pairs.[6]

The leaves can be small, needle-like, and curved, or they can be large, broadly ovate, and flattened.[7] They are spirally arranged, persistent, and usually have parallel venation.[2]

Like other conifers, they produce cones. Each tree can have both male and female cones (monoecious) or they can have only male or female cones (dioecious).[8]

Male cones are among the largest among all conifer cones, on average. They are cylindrical and drooping, somewhat resembling catkins. They are borne singly on the tips of branches or the axils of leaves. They contain numerous sporophylls arranged in whorls or spirals. Each has four to 20 elongated pollen sacs attached to the lower surface at one end. The pollen grains are round and do not possess wings or air sacs.[2][6][7]

Female cones are also very large. They are spherical to ovoid in shape and borne erect on thick, short shoots at branch tips. The numerous bracts and scales are either fused to each other or separate for half of their lengths.[2][6][7] The scales almost always bear only one seed on its upper surface, in contrast to two in true pines (family Pinaceae).[9] They are very large, among the largest seeds among conifers. They are dispersed by wind, usually using wing-like structures. On maturity, the female cones detach and fall to the ground.[2][6][7] Due to their size, they can cause serious injuries if they hit a person. The cones of the bunya bunya, Araucaria bidwillii, for example, weigh up to 10 kg (22 lb),[10] about the size and weight of a large pineapple. They can drop from heights of 23 m (75 ft).[9]

Classification and genera[edit]

Araucaria heterophylla
Agathis robusta
Wollemia nobilis

Araucariaceae is classified under the order Pinales, class Pinopsida of the division Pinophyta. The division includes all living conifers. Recently however, some authorities treat Araucariaceae as a separate order, Araucariales.[2]

Araucariaceae contains three extant genera and about 41 species.[5]

Image Genus Living Species Distribution
Araucaria Jussieu 19 living species found in New Caledonia (where 13 species are endemic), Norfolk Island, Australia, New Guinea, Argentina, Chile, and Brazil.
Agathis Salisbury New Zealand, Australia, Vanuatu, New Caledonia, Papua New Guinea, Indonesia, Malaysia, and the Philippines
Wollemia W.G. Jones, K.D. Hill & J.M. Allen endemic to Australia. It was known only from fossil remains before the discovery of the living species in 1994.

Phylogeny[edit]

Below is the phylogeny of the Pinophyta based on cladistic analysis of molecular data. It shows the position of Araucariaceae within the division.[11]

Pinaceae

Araucariaceae

Podocarpaceae

Sciadopityaceae

Cupressaceae

Cephalotaxaceae

Taxaceae

Relationships between living members of Araucariaceae.[12]

Araucariaceae

Araucaria

Wollemia

Agathis

Molecular evidence supports Araucariaceae and Podocarpaceae having diverged from each other during the late Permian.[13]

Distribution and habitat[edit]

Today, 41 species are known, in three genera: Agathis, Araucaria and Wollemia, distributed largely in the Southern Hemisphere.

By far the greatest diversity is in New Caledonia (18 species), with others in Australia, Argentina, New Zealand, Chile, southern Brazil, and Malesia. In Malesia, Agathis extends a short distance into the Northern Hemisphere, reaching 18°N in the Philippines.

Uses[edit]

Several species are very popular ornamental trees in gardens in subtropical regions, and some are also very important timber trees, producing wood of high quality. Several have edible seeds similar to pine nuts, and others produce valuable resin and amber. In the forests where they occur, they are usually dominant trees, often the largest species in the forest; the largest is Araucaria hunsteinii, reported to 89 m tall in New Guinea, with several other species reaching 50–65 m tall. A. heterophylla, the Norfolk Island pine, is a well-known landscaping and house plant from this taxon.

Skillful artisans in the Erzurum Province, Turkey, have used fossilized wood of Araucariaceae for centuries to manufacture jewelry and decorative items. It is known as "Oltustone", the name deriving from the town of Oltu, where it is most commonly excavated. Despite the fact that this semiprecious gemstone is classified as “stone”, wood anatomy reveals it was fossilized pieces of trunks of Araucariacea. Oltustone, also called ‘Black Amber’ is unique to Turkey. It is dull and black, but when polished, acquires an attractive black sheen.[14]

Fossil record[edit]

Fossils widely believed to belong to Araucariaceae include the form genera Araucarites (various), Agathoxylon and Araucarioxylon (wood), Brachyphyllum (leaves), Araucariacites and Dilwynites (pollen), and Protodammara (cones).

The oldest definitive records of Araucariaceae are from the Early Jurassic, though there are potential earlier Late Triassic records. Early representatives of Araucaria are widespread across both hemispheres by the Middle Jurassic, such as Araucaria mirabilis and Araucaria sphaerocarpa from the Middle Jurassic of Argentina and England respectively.[15] The oldest records of the Wollemia-Agathis lineage from the Cretaceous, including Emwadea microcarpa from the Albian aged Winton Formation of Australia[16] and Wairarapaia mildenhallii from the Albian-Cenomanian of New Zealand.[17][12] 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.[18]

See also[edit]

References[edit]

  1. ^ Poinar, George; Archibald, Bruce; Brown, Alex (1999). "New amber deposit provides evidence of Early Paleogene extinctions, paleoclimates, and past distributions" (PDF). The Canadian Entomologist. 131 (2): 171–177. doi:10.4039/ent131171-2. S2CID 85718312.
  2. ^ a b c d e f g "Araucariaceae". The Gymnosperm Database. Retrieved November 19, 2011.
  3. ^ "Araucariaceae: life history and ecology". University of California Museum of Paleontology. Retrieved November 19, 2011.
  4. ^ "Agathis australis". The Gymnosperm Database. Retrieved November 19, 2011.
  5. ^ a b Fu Liguo; Li Nan; Robert R. Mill (1999). "Araucariaceae" (PDF). Flora of China. 4: 9–10. Archived from the original (PDF) on May 24, 2011. Retrieved 2011-11-19.
  6. ^ a b c d James E. Eckenwalder (2009). Conifers of the world: the complete reference. Timber Press. p. 70. ISBN 978-0-88192-974-4.
  7. ^ a b c d Stuart Max Walters (1986). The European Garden Flora: Pteridophyta, Gymnospermae, Angiospermae. Cambridge University Press. p. 72. ISBN 978-0-521-24859-4.
  8. ^ Gerald Carr. "Araucariaceae". University of Hawaii. Retrieved November 19, 2011.
  9. ^ a b Wayne P. Armstrong. "The Araucaria Family: Araucariaceae". Wayne's Word, Paloma College. Archived from the original on December 3, 2011. Retrieved November 19, 2011.
  10. ^ "Araucaria biwillii (Bunya pine) description". The Gymnosperm Database. Retrieved 20 January 2023.
  11. ^ Derived from papers by A. Farjon and C. J. Quinn & R. A. Price in the Proceedings of the Fourth International Conifer Conference, Acta Horticulturae 2003; 615
  12. ^ a b Escapa, Ignacio H.; Catalano, Santiago A. (October 2013). "Phylogenetic Analysis of Araucariaceae: Integrating Molecules, Morphology, and Fossils". International Journal of Plant Sciences. 174 (8): 1153–1170. doi:10.1086/672369. hdl:11336/3583. ISSN 1058-5893. S2CID 56238574.
  13. ^ 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 (July 19, 2021). "Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms". Nature Plants. 7 (8): 1015–1025. doi:10.1038/s41477-021-00964-4. ISSN 2055-0278. PMID 34282286. S2CID 236141481.
  14. ^ Kutluk; et al. (2012). "First Report of Araucariaceae wood (Agathoxylon sp.) from the Late Cretaceous of Turkey". IAWA Journal. 33 (3): 319–326. doi:10.1163/22941932-90000097.
  15. ^ Leslie, Andrew B.; Beaulieu, Jeremy; Holman, Garth; Campbell, Christopher S.; Mei, Wenbin; Raubeson, Linda R.; Mathews, Sarah (September 2018). "An overview of extant conifer evolution from the perspective of the fossil record". American Journal of Botany. 105 (9): 1531–1544. doi:10.1002/ajb2.1143. PMID 30157290.
  16. ^ Dettmann, Mary E.; Clifford, H. Trevor; Peters, Mark (June 2012). "Emwadea microcarpa gen. et sp. nov.—anatomically preserved araucarian seed cones from the Winton Formation (late Albian), western Queensland, Australia". Alcheringa: An Australasian Journal of Palaeontology. 36 (2): 217–237. Bibcode:2012Alch...36..217D. doi:10.1080/03115518.2012.622155. ISSN 0311-5518. S2CID 129171237.
  17. ^ Cantrill, David J.; Raine, J. Ian (November 2006). "Wairarapaia mildenhallii gen. et sp. nov., a New Araucarian Cone Related to Wollemia from the Cretaceous (Albian‐Cenomanian) of New Zealand". International Journal of Plant Sciences. 167 (6): 1259–1269. doi:10.1086/507608. ISSN 1058-5893. S2CID 85365035.
  18. ^ 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.

Further reading[edit]