Ancient Flower Fossil Points To Underwater Origins

The newly discovered remains of the oldest, most complete flowering plant show it lived at least 125 million years ago, most likely underwater, said University of Florida (UF) paleobotanist David Dilcher. The discovery is reported in Friday's issue of the journal Science and was funded by the National Science Foundation (NSF).

"This Lower Cretaceous fossil challenges many assumptions about the origins of flowering plants," said Quentin Wheeler, director of NSF’s division of environmental biology, which funded the research. "Such fossil discoveries combine with advances in the analysis of molecular and morphological evidence from living plants to provide a classification that is the conceptual framework for evolutionary biology."

Although it had no petals, there is no question it was a flowering plant because of the presence of seeds enclosed in an immature fruit, a trait separating flowering plants from all other seed plants, he said.

The discovery is important because it provides clues about how these now-extinct ancestors evolved into modern living flowering plants, said Dilcher.

"Flowering plants are the dominant vegetation in the world today," he said. "They're the basic food crop and fiber source for the world's population.

It's useful for us to understand the relationships among flowering plants, especially in this day of molecular genetic manipulations.

"When you sit down in the morning and have a bowl of Wheaties or cornflakes, that's a flowering plant," he said. "When you eat a beef steak, that's from an animal that ate flowering plants. So, when we study this fossil, we're looking at the ancestry of what sustains us in the world today."

The plant was about 20 inches high with thin stems stretching up in the water to the surface with its pollen and seed organs extending above the water, Dilcher said.

The seeds probably dispersed in the water and floated up along the shore and germinated in shallow water, he said.

"The mysteries of the origin and radiation of the flowering plants remain among the greatest dilemmas facing paleontology and evolutionary biology," said William Crepet, plant biologist at Cornell University. "This fossil represents the first evidence of an angiosperm that is basal to all other angiosperms, yet that does not fit within any modern taxonomic group of angiosperms this makes it one of, if not the most important fossil flowering plant ever reported."

The fossil was found in China by local farmers who gave it to one of the paper's coauthors. It is much more complete than one found at a nearby site four years ago, which Dilcher also studied, and suggests origins in water that refreshed the dinosaurs, said Dilcher.

"After having only a fragment and trying to imagine what the whole plant was like, it was a great surprise to find leaves typical of a plant that lived underwater with characteristics very unique to flowering plants at such an early age in their history," he said.