Australian Botanists Unveil `New-Old' Tree
`Wollemi pine' may be more closely related to fossilized plants than to living species
ITS knobbly bark looks like a chocolatey breakfast cereal. Its trunk grows up to one meter in diameter (3.2 feet) and up to 40 meters high (131.2 feet). Its leaves, even the mature ones, are light green, with a complex, unusual structure. Its upper branches carry bright green female cones and brown, cylindrical male ones. Until August 1994 nobody had the least notion it existed - except perhaps in fossil form.
Botanists studying this ``new'' tree believe it may be more closely related to certain fossils than to any living species. They even think it may be not only a new species, but also a new genus.
Although the tree is certainly of the botanical family Araucariaceae, the same as Chile's monkey puzzle tree, it still awaits a full official name. Meanwhile, it has been given an everyday name the ``Wollemi pine.''
It was found 200 kilometers (124.2 miles) from the Australian city of Sydney. Botanists thought they knew Wollemi National Park. But David Noble, a field officer with the National Parks and Wildlife Service (NPWS), out bushwalking, noticed about 40 strange trees. They were in various stages from seedlings to apparently mature specimens, in a gorge of subtropical rain forest.
The discovery has received far more media attention worldwide than most newly discovered plants do. In late December, for example, a new genus in the Proteaceae family of trees and shrubs was also discovered in Australia. But it has been virtually ignored by the media. This second discovery is ``of great significance and equally exciting'' according to Australian botanist Ken Hill.
But what apparently most grabbed the media about the Wollemi pine, when the discovery was announced mid-December after more plant material was collected, was that the label ``Jurassic'' was applied to the tree.
``Jurassic Pine Discovered in Blue Mountains'' the heading of the NPWS press release blared. The idea proved irresistible to New South Wales Minister for the Environment Chris Hatcher. ``This is like finding a dinosaur in your backyard,'' he exclaimed, adding: ``The Wollemi pines are truly living fossils as their closest relations are extinct plants only found in fossils from the Jurassic and Cretaceous periods about 65 million to 200 million years ago.''
Some botanists believe the discovery of the tree is exciting enough without making over-the-top claims. They compare its importance to the discovery in China in the 1940s of the dawn redwood (Metasequoia glyptostroboides), similarly thought extinct and known only in fossils.
Mr. Hill - who is investigating the new tree at the Royal Botanic Gardens Sydney using DNA testing and scanning electron microscopy - puts things more soberly. ``Finding a dinosaur would be finding a whole order of organisms that is extinct. It would be finding a living representative of one of those. Whereas this is a genus that was extinct, but there are other [living] genera in that same family. So there are other related things ... in existence.''
Those related living ``things'' are all in the family Araucariaceae. They are trees like the monkey puzzle and Australia's hoop pine, Bunya pine, and Norfolk Island pine (all of the genus Araucaria), as well as the Kauri pine of New Zealand (of the genus Agathis). These trees can also be related back to ancient fossils. But then so can a sizeable number of other living plant genera, various ferns for example.
Hill also points out that the group of fossils (which ``are actually just leaf fragments'') in which he is finding the closest relating forms to these ``new'' living leaves are not Jurassic, but ``from 50 to 60 million years ago.'' By this period, the Tertiary age, dinosaurs were long extinct.
Nevertheless, the Arucariaceae family is known to have had a worldwide distribution in the Jurassic and Cretaceous periods. So the newly discovered tree has remarkably old ancestors. But for it to be more nearly related to Tertiary fossils than to any living member of the two known genera (Araucaria and Agathis) of the Araucariaceae family, still makes its find exceptional. Hill describes the fossil fragments and the living leaves as ``a very close match.''
Before the Wollemi pine is given its final name - possibly making history as the third genus of the family Araucariaceae - it looks as though there may be some considerable discussion.
Chris Page, the botanist specializing in conifer conservation at the Royal Botanic Garden Edinburgh, says: ``As far as I can tell [from photos], it looks as if it might be halfway between living monkey puzzles (Araucaria araucana) and living Agathis - two very different-looking members of the Araucariaceae family. It could be an evolutionary link between the two.''
At first, however, he questioned Hill's assertion that the Wollemi pine is not just a new species, but a new genus. He wanted to know what the fossil was named. He suggested the tree might be more accurately called a ``living fossil'' rather than ``a new genus and species.''
Hill's answer was that the name given to the fossils was ``Araucarioides.'' But Page dismissed this as a ``ragbag genus.''
Both botanists agree that there is no requirement in botanical nomenclature to follow the name given to a fossil when naming a living plant even if it is very like it. But Page argues for doing so if possible, so as to achieve conformity between the names of fossils and living plants. Hill, on the other hand, simply says that this tree will be given a new genus and species name, and that fossil names ``do not have priority.''
Meanwhile efforts to propagate the tree in ``captivity'' are under way, for backup conservation. Test-tube culture of immature seeds looks hopeful. And one seedling taken from the site is growing well in a greenhouse.
The trees' relative inaccessibility and dampness of habitat may be two reasons they have survived the threat of fires and humans. The question now is can they be kept secret.