Wollemia

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iWollemia

Young specimen in a botanical garden protected from theft by a steel cage

Scientific classification

Kingdom:	Plantae
Division:	Pinophyta
Class:	Pinopsida
Order:	Pinales
Family:	Araucariaceae
Genus:	Wollemia
Species:	W. nobilis

Binomial name

Wollemia nobilis
W.G.Jones, K.D.Hill & J.M.Allen

Wollemia nobilis is a coniferous tree that was discovered in 1994 in a remote series of narrow, steep-sided sandstone gorges in a mild temperate-zone rainforest wilderness area of the Wollemi National Park in New South Wales, 150 km north-west of Sydney.

In popular literature, the tree has been named "Wollemi Pine", although it is not a member of the pine family, but is related to Kauri and Araucaria in the family Araucariaceae.

Wollemia is an evergreen tree reaching 25–40 m tall. The bark is very distinctive, dark brown and knobbly, quoted as resembling chocolate-coated Rice Krispies. The tree coppices readily, and most specimens comprise multi-trunk clumps of trunks thought to derive from old coppice growth. The branching is unique in that nearly all the side branches never have further branching. After a few years, each branch either terminates in a cone (either male or female) or ceases growth. After this, or the cone becomes mature, the branch dies. New branches then arise from dormant buds on the main trunk. Rarely, a side branch will turn erect and develop into a secondary trunk, which then bears a new set of side branches.

The leaves are flat linear, 3–8 cm long and 2–5 mm broad. They are arranged spirally on the shoot but twisted at the base to appear in two or four flattened ranks. The seed cones are green, 6–12 cm long and 5–10 cm in diameter, and mature about 18–20 months after pollination. They disintegrate at maturity to release the seeds. The male (pollen) cones are slender conic, 5–11 cm long and 1–2 cm broad.

[edit] Discovery

The discovery, on or about 10 September 1994, by David Noble, a field officer of the Wollemi National Park in Wentworth Falls, in the Blue Mountains, only occurred because of his adventurous bushwalking and rock climbing abilities. Noble had good botanical knowledge, and quickly recognised the trees as unusual and worthy of further investigation. Returning with specimens, and expecting someone to be able to identify the plants, Noble soon found that they were new to science. Further study would be needed to establish its relationship to other conifers. The initial suspicion was that it had certain characteristics of the 200-million-year-old family Araucariaceae, but was not the same as any living species in the family. For this reason the species is described as a living fossil.

Comparison with living and fossilised Araucariaceae proved that it was a member of that family, and it was placed into a new genus with the other extant genera Agathis and Araucaria. Fossils resembling Wollemia and possibly related to it are widespread in Australia, New Zealand and Antarctica, but Wollemia nobilis is the sole living member of its genus.

Fewer than a hundred trees are known to be growing wild, in three localities not far apart. Genetic testing has revealed that all the specimens are genetically indistinguishable, suggesting that the species has been through a genetic bottleneck in which its population became so low (possibly just one or two individuals) that all genetic variability was lost.

In November of 2005, wild-growing trees were found to be infected with Phytophthora cinnamomi. New South Wales park rangers believe the virulent fungus was introduced by unauthorised visitors to the site, whose location is still undisclosed to the public.

[edit] Cultivation and uses

A propagation programme has culminated with the Wollemi Pine commercially available in Australia from 1st April 2006. It will be commercially released in other countries during 2006. It may prove to be a valuable tree for ornament, either planted in open ground or for tubs and planters. It is also proving to be more adaptable and cold-hardy than its restricted subtropical distribution would suggest, tolerating temperatures between -5°C and 45°C, with reports that it can survive down to -12°C. It also handles both full sun and full shade. Like many other Australian trees, Wollemia is susceptible to the pathogenic fungus Phytophthora cinnamomi, so this may limit its potential as a timber tree.