Flowers discovered growing in Western Australia are living fossils
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Some tiny plants growing in Western Australian swamps between Geraldton and Esperance may be among the world's oldest flowering species.
An international research team has shown that Hydatella - and their close cousins the Trithuria - may have evolved during the Cretaceous period, more than 135 million years ago when Australia was still part of the super-continent Gondwana in the age of the dinosaurs.
Dr Terry Macfarlane, a botanist with the Department of Environment and Conservation's Science Division in Manjimup, said the new findings, published in the latest issue of the journal Nature, were both exciting and surprising.
"The genus Hydatella includes a small group of aquatic herbs native to Australia, New Zealand and India", Dr Macfarlane said.
"They have small flowers with a very simple structure and so scientists have been uncertain of their closest relative," he said. "They were previously thought to be related to grasses."
The researchers used DNA sequencing to pinpoint the evolutionary position of the Hydatella family.
"We now know that these plants are most closely related to the water lilies, which by contrast have some of the biggest and most striking of all flowers," Dr Macfarlane said.
The new findings have thrown the international spotlight on Western Australia as scientists try to understand more about the earliest flowering plants on earth.
"There are more species of Hydatella in south-west Australia than any other region in the world," Dr Macfarlane.
"DEC has been assisting the international research effort by conducting extensive field and laboratory studies and providing information and plant material for scientific
analysis." Dr Macfarlane said that in the process of assisting their international colleagues, DEC botanists had gathered much knowledge to help in the conservation of Hydatella in WA.
"Five species of Hydatella and Trithuria are found in south western WA. Two are listed as rare and one is on DEC's priority flora list," he said.
"The plants grow in seasonal swamps, wetlands and granite rock pools at scattered locations from Geraldton to east of Esperance but a species also is found in the Kimberley.
"They are annuals, growing each year from seeds after the swamps and pools fill with water from the rains. They spend the growing season in wet mud or under shallow water.
"The plants are only 10 to 50 mm tall. The red flowers are very simple and they do not have petals."
Dr Macfarlane said the latest discovery shed new light on the evolution of the plant kingdom.
"The research shows that Hytadella pre-date the division of flowering plants into monocots (narrow-leafed plants) and dicots (broad-leafed plants).
"One of the researchers has likened the discovery to finding a lizard today that actually is a living dinousaur.
"It also is further evidence that protecting wetlands and maintaining water quality is vital for further scientific discoveries through conserving primitive and interesting plants."
More detailed information on Hydatella and Trithuria is available on DEC's FloraBase website at www.naturebase.net/florabase.
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