Araucaria

Araucaria
Fossil range: 250–0 Ma
Jurassic[1]- recent
Araucaria columnaris
Araucaria columnaris
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Araucariaceae
Genus: Araucaria
Juss.
Species

See text.

Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. There are 19 species in the genus, with a highly disjunct distribution in New Caledonia (where 13 species are endemic), Norfolk Island, eastern Australia, New Guinea, Argentina, Chile, and southern Brazil.

Contents

Description

Araucaria are mainly large trees with a massive erect stem, reaching a height of 30-80 m. 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.

The trees are mostly dioecious, with male and female cones found on separate trees, though occasional individuals are monoecious or change sex with time. The female cones, usually high on the top of the tree, are globose, and vary in size between species from 7-25 cm diameter. They contain 80-200 large, edible seeds, similar to pine nuts though larger. The male cones are smaller, 4-10 cm long, and narrow to broad cylindrical, 1.5-5 cm broad.

Distribution

Many if not all current populations are relicts, and of restricted distribution. They are found in forest and maquis shrubland, with an affinity for exposed sites. These columnar trees are living fossils, dating back to early in the Mesozoic age. Fossil records show that the genus also formerly occurred in the northern hemisphere until the end of the Cretaceous period.

Uses

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 and the edible seeds.

Etymology of name

The genus is familiar to many people as the genus of the distinctive Monkey-puzzle Araucaria araucana. The genus is named after the Arauco Indians of central Chile and south-west Argentina whose territory incorporates natural stands of this species, where it is known as the Pehuén. These Native Americans, who name themselves the Pehuenche ('people of the Pehuén'), harvest the seeds extensively for food. No distinct vernacular name exists for the genus; many are erroneously called 'pine', despite their being only very distantly related to pines (Pinus).

Classification and species list

Petrified cone of Araucaria sp. from Patagonia, Argentina dating from the Jurassic Period (approx. 210 mya)

There are two sections in the genus, sometimes treated as separate genera:

Gallery

External links

References

  1. Hiroaki, Setoguchi; Osawa, Takeshi Asakawa; Pintaud, Jean Christophe; Veillon, Jean-Marie (1998). "Phylogenetic relationships within Araucariaceae based on rbcL gene sequences". American Journal of Botany 85:11: 1507–1516.