UPDATE - sourced from Wikipedia, October 2008
A team of scientists working at the Plant Science Department, University of Tasmania, and Parks and Wildlife Service, Department of Environment and Land Management, Tasmania (Jasmyn Lynch, Jayne Balmer, Dr Greg Jordan, Dr Joycelyne Cambecedes, Richard Barnes and Dr Rene Vaillancourt) have discovered the oldest living plant individual known to date.
Lomatia tasmanica (common name King's Holly), which is a member of the Proteaceae family, is known by only one population which is located in the world heritage area of Southwest Tasmania, Australia. It grows along creek gullies in remnant rainforest.
An isozyme analysis found that it possessed zero genetic diversity (all living plants of the species are exactly the same). On the other hand, a closely related species (Lomatia tinctoria "Guitar Plant") which also propagates vegetatively had a normal level of genetic diversity. Chromosome counts reveal that Lomatia tasmanica had a triploid chromosome number and this generic information explains the observations that L. tasmanica appears to be sterile (it flowers but never forms mature fruits) and shows little morphological variability. This evidence strongly suggests that the entire species is a single clone that propagates vegetatively.
The L. tasmanica clone (spanning 1.2 km) is the second longest in the world after the box-huckleberry clone (Gaylussacia brachycera) in North America (Pennsylvania) which is reported to be 2 km in length. A clone of this size must be very old. Indeed, under the cold climate of Southwest Tasmania, vegetative propagation is likely to be very slow.
Fortunately, fossil leaf fragments, identical to living L. tasmanica were found in a fossil deposit 8.5 km of the extant population. These permit a more precise age estimate. These fossils have a C14 (carbon 14) age of 43,600 years. The oldest reported plant clone is the box-huckleberry which was aged at 13,000 years (Wherry 1972). The oldest living tree is believed to be a bristlecone pine (Pinus aristata) in Arizona which has been dated using dendrochronology at 4,700 years. Lomatia tasmanica appears to be the oldest living plant individual known to date.
A manuscript that details all the analysis has been submitted to the Australian Journal of Botany.
Literature cited and further reading:
Cook, R.E. (1983)
Clonal plant populations. American Scientist 71, 244-253. Vaillancourt, R.E.,
G. Jordan, J, Cambacedes and A.J.J. Lynch, 1996.
Is Lomatia tasmanica a 43,000 year old clone? Presented at the Royal Botanical Gardens
Commemorative Conference, Proteaceae Symposium, Sept.9 to Oct.5 Melbourne, Vic.
Wherry, E.T. (1972).
Box-huckleberry as the oldest living protoplasm. Castanea 37, 94-95.
FURTHER UPDATE (SEPTEMBER 8, 2009)
Botanist Natalie Tapson from the Royal Tasmanian Botanical Gardens says all 500 stands of the tree - produced from one original plant - are under threat from the deadly root rot disease phytophthora, which is spreading rapidly through grass plains surrounding its habitat. She says an insurance population is being established by creating clones through tissue cultures. "When we first started we lost all the plants almost straight away," she said. "We now have about 20 plants in tissue culture that have survived for about eight months and we're hopeful that we can keep tubing these on and get more and more plants that way."
A welcome "birthday" present for the plant's original discoverer, Denny King - who would have turned 100 on September 9.