Gymnosperms (Seed Producing Plants: Conifers, Cycads, Ginkgo) • Earth.com

Norfolk Island Pine

(Araucaria heterophylla)

galery
en

Description

Araucaria heterophylla (synonym A. excelsa) is a species of conifer. As its vernacular name Norfolk Island pine (or Norfolk pine) implies, the tree is endemic to Norfolk Island, an external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia. It is not a true pine, which belong to the family Pinaceae, but instead is a member of the genus Araucaria, in the family Araucariaceae which also contains the monkey-puzzle tree. Members of Araucaria occur across the South Pacific, especially concentrated in New Caledonia (about 700 km or 430 mi due north of Norfolk Island) where 13 closely related and similar-appearing species are found. It is sometimes called a star pine, Polynesian pine, triangle tree or living Christmas tree, due to its symmetrical shape as a sapling. It is a slow growing tree, reaching a height of 50–65 m (160–210 ft), with straight vertical trunks and symmetrical branches, even in the face of incessant onshore winds that can contort most other species. From the straight trunk, it emits its branches almost horizontal or slightly oblique, in number of five, forming floors; the plane of each floor is a perfect pentagon. If kept indoors, the tree remains smaller. The gray-brown bark falls off in fine scales. At the more or less horizontal to sometimes hanging branches, the branches are four to seven in regular whorls. The young leaves are soft and awl-shaped, 1–1.5 cm (3⁄8–9⁄16 in) long, about 1 mm (1⁄32 in) thick at the base on young trees, and incurved, 5–10 mm (3⁄16–13⁄32 in) long and variably 2–4 mm (3⁄32–5⁄32 in) broad on older trees. The thickest, scale-like leaves on coning branches are in the upper crown. The cones are squat globose, 10–12 cm (4–5 in) long and 12–14 cm (5–6 in) diameter, and take about 18 months to mature. They disintegrate at maturity to release the nut-like edible seeds. The seeds have a length of 2.5 to 3 cm (1 to 1+1⁄8 in) and a diameter of about 1.2 cm (1⁄2 in) with wide wings. There are four cotyledons present. It is a dioecious tree (male and female flowers in different plants), although it can also be monoecious.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Coniferophyta
Class: Pinopsida
Order:Pinales
Family:Araucariaceae
Genus:Araucaria
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