WASHINGTON -- Researchers believe they have discovered fossil evidence of the world's oldest flower, at 142 million years: a spindly twig with peapod-shaped fruit and a woody stem that looks nothing like a rose, an apple blossom or a daisy.
The fossil is from an early evolutionary stage when plants were just developing the flowering system that later evolved into fruit, grain, brilliantly colored and fragrant flowers and food for many animals, said David Dilcher, a University of Florida biology professor.
"It would have been a very different world if early flowering plants like this one had not been successful," said Dilcher, co-author of a study in Friday's edition of the journal Science. "There would have been no apples, no Wheaties in the morning, no corn on the cob, no potatoes, no rice or other grains."
All of the common plant food sources came into existence after plants evolved the ability to make flowers that attracted insects and other pollinators and then grew into fruit.
The flowering plant fossil was found in a rock formation of limestone and volcanic ash layers in China, near the town of Beipiao, about 250 miles northeast of Beijing. The rock beds were once on the bottom of a lake that periodically was showered with volcanic ash, Dilcher said.
Plants and animals that sank to the lake bottom became covered with sediment and turned into fossils. Villagers digging in the fossil beds have unearthed dinosaurs, insects, birds and plants from millions of years ago, but this is the first time a flowering plant has been uncovered.
The discovery has been age-dated at 142 million years by Chinese scientists, Dilcher said. The oldest previously known flowering plant was about 130 million years old. Chinese researchers, including the researcher who found the fossil, asked Dilcher to analyze it.
The ancient plant lacks the petals and shape that most people associate with flowers.
"It doesn't have any beautiful or showy flowers, but it is a flowering plant because it has fruit that enclose seeds," said Dilcher.
Botanists hailed the discovery as an important advance in understanding how plants evolved.
"To the world of botany, it's a discovery of the same scale as understanding the details of why the dinosaurs became extinct," said William L. Crepet, a Cornell University professor.
The plant specimen is about three inches long, with two parts that appear to be joined branches. Along the branches are what appear to be paired leaves. But Dilcher said the whole thing, branches and leaves, is actually a flower. That is because some of the leaves are closed, like peapods, and contain seeds. The peapods are considered the fruit of the flower, he said.
Indeed, the plant "may have been the first evolutionary experiment in enclosing seeds and trying to attract pollinators," Dilcher said.
Plants first developed seeds some 350 million years ago. Developing flowers and attracting insect pollinators was the next great leap in plant evolution, and eventually in animal evolution, he said.
Plants, in effect, evolved ways to enlist the cooperation of animals to reproduce. They developed ways to attract pollinators, such as bees. They developed ways to have seeds transported by making fruit, such as apples, that were eaten by animals who then dropped the seeds elsewhere.
"Flowering plants were the first advertisers in the world," said Delcher. "They managed to gain the cooperation of animals by learning to say `Hey, I smell good. I've got a reward for you. Come and visit me."'
Plants reached the stage of having bright blossoms, sweet fragrance and flowing nectar about 55 million years ago, some 90 million years after the Chinese flower fossil.
"These changes all came in progressive steps," said Delcher. "They helped flowering plants become the most successful of all of the plants."