| Amber gives clues to origin of flowers|
|Scientists have discovered a piece of fossilised amber that came from a plant living more than 300 million years ago.|
The research, published in a the latest edition of Science, shows plants of the day were far more sophisticated than previously thought.
PhD student and lead author of the paper, Paul Sargent Bray of Macquarie University in Sydney, says different plants produce different types of amber, or fossilised tree resin.
"You can tell what kind of plant is producing what kind of amber by the resin's chemistry."
Sargent Bray says he found the amber in a piece of coal during a field trip while studying at Southern Illinois University in the US.
When he studied the resin's chemistry he found it was very similar to that produced by some modern day plants.
The ancient amber has a very similar chemical makeup to the resin produced by angiosperms, more commonly known as flowering plants, says Sargent Bray.
But he says angiosperms only start showing up in the fossil record at the beginning of the Cretaceous period, around 120 million years ago.
The coal containing the amber dates back at least 300 million years, which is known as the Carboniferous period, he says.
Organic geochemist and Sargent Bray's supervisor Dr Simon Green, also of Macquarie University, says the earth was a very different place 300 million years ago.
"It was dominated by tropical jungles, and it was much hotter and wetter."
But there is no evidence of flowering plants back then, says Green .
He says the dominant plants were gymnosperms, fern like plants that are predominantly extinct today.
Sargent Bray says the big question is when did the angiosperms diverge from their ancestors, the gymnosperms.
"The amber work doesn't answer that question, but it provides some perspective on parts of the biology that might be involved in the divergence," he says.
Sargent Bray says more amber specimens need to found between the Carboniferous and Cretaceous period to gain a better understanding of the origin of flowering plants.
He says they're not suggesting that flowering plants existed earlier than was previously thought, "but perhaps the biology started to appear a lot earlier than expected."
Green agrees. "It sheds some light on the origin of flowering plants."