Wollemia

Wollemia
Fossil range: Mid-Cretaceous; recent
Young specimen in a botanical garden protected from theft by a steel cage
Conservation status
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 is a genus of coniferous tree in the family Araucariaceae. The Australian species Wollemia nobilis is the sole species in the genus Wollemia and was discovered in 1994 in a remote series of narrow, steep-sided sandstone gorges near Lithgow in temperate rainforest wilderness area of the Wollemi National Park in New South Wales, 150 kilometres north-west of Sydney.

In both the botanical and popular literature, the tree has been almost universally dubbed the Wollemi Pine, although it is not a true pine (genus Pinus) nor a member of the pine family (Pinaceae), but rather is related to Agathis and Araucaria in the family Araucariaceae. The oldest fossil of the Wollemi tree has been dated to 200 million years ago.[1]

Contents

Description

Wollemia nobilis, Palmengarten, Frankfurt/Main, Germany

Wollemia nobilis is an evergreen tree reaching 25–40 m (80-130 feet) tall. The bark is very distinctive, dark brown and knobbly, quoted as resembling Coco Pops breakfast cereal.[2] The tree coppices readily, and most specimens are multi-trunked or appear as 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 when 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.

Wollemia nobilis leaves

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.

Discovery

Wollemia nobilis - young cone

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.[3] 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 similar to any living species in the family. Comparison with living and fossilised Araucariaceae proved that it was a member of that family, and it has been placed into a new genus with 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. The last known fossils of the genus date from approximately 2 million years ago.[4] It is thus described as a living fossil, or alternatively, a Lazarus taxon.

Fewer than a hundred trees are known to be growing wild, in three localities not far apart. It is very difficult to count them as most trees are multistemmed and may have a connected root system. 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 2005, wild-growing trees were found to be infected with Phytophthora cinnamomi. New South Wales park rangers believe the virulent water mould was introduced by unauthorised visitors to the site, whose location is still undisclosed to the public.

Cultivation and uses

Wollemia nobilis cultivated

A propagation programme made Wollemi Pine specimens available to botanical gardens, first in Australia in 2006 and subsequently throughout the world. 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 (23° and 113°F), with reports that it can survive down to -12°C (10°F). A grove of Wollemi Pines planted in Inverewe Garden, Scotland, believed to be the most northerley location of any successful planting, have survived temperatures of -7°C, recorded in January 2010.[5] It also handles both full sun and full shade. Like many other Australian trees, Wollemia is susceptible to the pathogenic water mould Phytophthora cinnamomi, so this may limit its potential as a timber tree.[6]

Notes

  1. ↑ Fact Sheet: Wollemi Pine
  2. ↑ James Woodford, The Wollemi Pine: The incredible discovery of a living fossil from the age of the dinosaurs, (Revised Edition), The Text Publishing Company, 2002, ISBN 1-876485-74-4
  3. ↑ "The Wollemi Pine — a very rare discovery". Royal Botanic Gardens, Sydney. http://web.archive.org/web/20050323093506/http://www.rbgsyd.gov.au/information_about_plants/wollemi_pine. Retrieved 2007-02-08. 
  4. ↑ "Wollemi Pine research — Age & Ancestry". Royal Botanic Gardens, Sydney. http://web.archive.org/web/20050323160650/www.rbgsyd.gov.au/information_about_plants/wollemi_pine/age_and_ancestry. Retrieved 2007-03-01. 
  5. ↑ "Jurassic tree survives big chill in trust garden". BBC, London. 2010-11-01. http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/8452506.stm. Retrieved 2010-13-01. 
  6. ↑ "Wollemi Pine research — fungal associations & pathogens". Royal Botanic Gardens, Sydney. http://web.archive.org/web/20050501202059/www.rbgsyd.gov.au/information_about_plants/wollemi_pine/research_projects?p=424. Retrieved 2007-02-08. 

References and external links