Ancient clonal tree, King's lomatia, excites scientists in Tasmania's remote south west
/ By Zoe KeanBefore the last ice age, deep in the mountains and valleys of south-western Tasmania an unusual little sprout grew from a seed.
The plant grew and grew, eventually unfurling deep red flowers, but as the curled petals dropped to the ground no viable seeds formed.
Today, its wild population is limited to just a 1.2 kilometre square and it may be among the world's oldest clonal plants — having grown from a single seed, genetically cloned many times over through the millennia.
New "individuals" formed when underground rhizomes struck out and new shoots appeared. Or when a limb would break off, form its own roots and start to grow. But these new plants were genetically identical, with no sexual reproduction scrambling their genetics and making new seeds.
Meet King's lomatia — Lomatia tasmanica. And it's critically endangered.
When Jayne met King's lomatia
It was 1987, at least 43,000 years after the little seed sprouted, when a young ecologist by the name of Jayne Balmer first saw King's lomatia.
The species' ancient history was not understood at that time, but "it was still an exciting and mysterious plant," Dr Balmer said.
She was on a break from her work with the Parks Service near Melaleuca when the scientist made the tough solo trek to find it.
After having to "bash through scrub", Dr Balmer had nearly given up on finding the ancient plant, when she sat down on a creek bank for a rest and "lo and behold, at my feet were all these leaves."
"I was mesmerised and hooked on finding out more," she said.
The "mysterious plant" had first come to scientific attention when tin miner, environmentalist, bushman, and artist Charles Denison "Deny" King found a patch in 1934.
It was named for him by Winifred Curtis in 1967.
Mr King, who lived with his family in Tasmania's remote south west for 55 years, gave Dr Balmer directions to the one existing population of the plant.
"The maps in those days were pretty lousy," she said.
To guide her there, she gave Mr King an aerial photograph of the area.
"He just put an X on the spot and said, 'Here is where you go.'"
Unravelling its many mysteries
While mining for tin, Mr King had discovered rocks rich in diverse botanical fossils.
He alerted researchers to his finds and encouraged them to investigate.
Fatefully, palaeobotanist Greg Jordan from the University of Tasmania was one of the researchers who took him up on that offer.
Among the wealth of preserved species, Professor Jordan found fossilised King's lomatia. He published his findings in 1991, the same year that Mr King died.
"I was pretty excited … but we did not know much about King's [lomatia] then except that it was a rare and endemic species from that area," Professor Jordan said.
The fossils would be carbon-dated to 43,600 years old, but their full significance would not be clear until genetic analysis was conducted on the living population.
Genetic revolution of the 1990s
Dr Balmer was in the field with scientist Jasmine Lynch when she collected the samples she would later use to show each supposedly "individual" plant was genetically identical and therefore a clone originating from a single seed.
"That was mind-blowing," Dr Balmer said.
Genetic research has since uncovered ancient clonal plants over large areas, such as a seagrass in the Mediterranean thought to be more than 200,000 years old — but this was a new idea at the time.
Genetic analysis also solved the mystery as to why the plant was sterile.
Instead of having two sets of chromosomes, King's lomatia has three, making it triploid, and it is very difficult for triploid organisms to reproduce.
"The process of sexual reproduction is actually about splitting things in two … if you've got three, it's a real mess," Professor Jordan explained.
Mystery solved?
The evidence was in. The entire population was identical, could not reproduce sexually, and there was a fossil showing it lived at least 43,600 years ago.
To some, surely this whole species was descended from one founding seed?
But Professor Jordan says there is "a weakness in the argument".
No-one knows what the plant that produced the founding seed was, although Lomatia tasmanica is in the same family as the waratah, grevillea, macadamia, and protea.
If the fossilised leaf was a double-chromosome look-alike it might not represent an ancient clone of today's plants, although this is not likely.
"A triploid is almost always very different from the parent source because the process of becoming triploid changes it a lot," Professor Jordan says.
"Here we have an individual clone that has had no evolutionary change [and] has survived through the ice ages.
"Through massive climate change it just sat there and survived and survived somehow. That's really astonishing."
Long live the king?
Dr Balmer paid a rare visit to the King's lomatia this year to check on its welfare.
She is now a senior ecologist for Tasmania's Department of Natural Resources and Environment and was "reassured" that are were doing well.
"[The species is] vulnerable to fire … and because it's located over such a small area, disease could easily just come in and wipe it out," she said.
To ensure the plants' safety, the location is kept secret and even researchers only go there if necessary.
But some plants do live among us. At Hobart's Royal Tasmanian Botanical Gardens an insurance population of plants has been cloned since 2004 to ensure its survival.