Fossil plant puts sunflower origin in South America

Fossils of the Asteraceae, or aster, family are really hard to come by and most are just pollen grains. However, Argentine scientists found a fossil of two flower heads in pristine condition showing several features of the aster family.

Botanist Liliana Katinas told Reuters on Thursday that researchers had struggled to pinpoint the origin of the family but the fossil found in 2002 in southern Argentina's wind-sept Patagonia region suggests they first evolved in South America.

"If one was to say where the origin of this family is, I'd say in South America ... in the Patagonia," said Katinas, who works for Argentina's National Council for Scientific and Technical Research and is part of the team of scientists that have been studying the fossil for the past two years.

"We've found a flower head whose pollen -- after analysis by a pollen specialist in the group -- is at the base of the evolutionary tree ... it's at the bottom. And where did we find it? We found it in Patagonia, in South America," she said.

The scientists released the results of their study this week in an article in the journal Science.

The fossil is about 50 million years old and features two clearly visible flowers complete with stems, petals and winged seeds.

Marigolds, dahlias and chrysanthemums also are members of the aster family, which includes between 20,000 and 30,000 plants. Katinas said this type of plant is found on every continent except Antarctica.

She said the discovery is akin to the finding of the first dinosaur fossil and that further research is needed to determine how the aster family diversified and spread throughout the world.

"We have to keep investigating ... This is getting really interesting," Katinas said.

(Reporting by Juan Bustamante; Writing by Eduardo Garcia; Editing by Bill Trott)