Araucaria are mainly large trees with a massive erect stem, reaching a height of 5–80 metres (16–262 ft). The horizontal, spreading branches grow in whorls and are covered with leathery or needle-like leaves. In some species, the leaves are narrow, awl-shaped and lanceolate, barely overlapping each other; in others they are broad and flat, and overlap broadly.[3]
The trees are mostly dioecious, with male and female cones found on separate trees,[4] though occasional individuals are monoecious or change sex with time.[5] The female cones, usually high on the top of the tree, are globose, and vary in size among species from 7 to 25 centimetres (3 to 10 in) in diameter. They contain 80–200 large edible seeds, similar to pine nuts, though larger. The male cones are smaller, 4–10 cm (1+1⁄2–4 in) long, narrow to broad cylindrical, and 1.5–5 cm (1⁄2–2 in) broad.
The genus is familiar to many people as the genus of the distinctive Chilean pine or monkey-puzzle tree (Araucaria araucana). The genus is named after the Spanish exonymAraucano ("from Arauco") applied to the Mapuche of south-central Chile and south-west Argentina, whose territory incorporates natural stands of this genus. The Mapuche people call it pehuén, and consider it sacred.[3] Some Mapuche living in the Andes name themselves Pehuenche ("people of the pehuén") as they traditionally harvested the seeds extensively for food.[6][7]
No distinct vernacular name exists for the genus. Many are called "pine", although they are only distantly related to true pines, in the genus Pinus.
Genetic studies indicate that the extant members of the genus can be subdivided into two large clades – the first consisting of the sectionsAraucaria, Bunya, and Intermedia; and the second of the strongly monophyletic section Eutacta. Sections Eutacta and Bunya are both the oldest taxa of the genus, with Eutacta possibly older.[13]
Taxa marked with † are extinct.
Section Araucaria.Wilde and Eames, 1952 Leaves broad; cones more than 12 cm (4.7 in) diameter; seed germination hypogeal. Syn. sect. Columbea; sometimes includes Intermedia and Bunya
Araucaria angustifolia – Paraná pine (obsolete: Brazilian pine, candelabra tree); southern and southeastern Brazil, northeastern Argentina.
Araucaria araucana – monkey-puzzle or pehuén (obsolete: Chile pine); central Chile & western Argentina.
By far the greatest diversity exists in New Caledonia, likely due to a relatively recent adaptive radiation, as all New Caledonian species are more closely related to each other than they are to other Araucaria.[17][3] Much of New Caledonia is composed of ultramafic rock with serpentine soils, with low levels of nutrients, but high levels of metals such as nickel.[22] Consequently, its endemic Araucaria species are adapted to these conditions, and many species have been severely affected by nickel mining in New Caledonia and are now considered threatened or endangered, due to their habitat lying in prime areas for nickel mining activities.
Some evidence suggests that the long necks of sauropod dinosaurs may have evolved specifically to browse the foliage of tall trees, including those of Araucaria. An analysis of modern Araucaria leaves found that they have a high energy content but are slow fermenting, making their ancestors a likely attractive target.[23]
Some of the species are relatively common in cultivation because of their distinctive, formal symmetrical growth habit. Several species are economically important for timber production.
Food
For broader coverage of this topic, see Conifer nuts.
The edible large seeds of A. araucana, A. angustifolia and A. bidwillii — also known as Araucaria nuts,[24] and often called, although improperly, pine nuts — are eaten as food, particularly among the Mapuche people of Chile and southwest Argentina, the Kaingang people in Southern Brazil and among Native Australians.[3]
In South America Araucaria nuts or seeds are called piñas or piñones in Spanish and pinhões in Portuguese, like pine nuts in Europe.
^Mary E. Dettmann; H. Trevor Clifford (2005). "Biogeography of Araucariaceae"(PDF). In J. Dargavel (ed.). Australia and New Zealand Forest Histories. Araucaria Forests. Occasional Publication 2. Australian Forest History Society. pp. 1–9. Archived from the original(PDF) on 2009-09-13.
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