Photo: Florida Museum of Natural History

Paleontologists first found the fossil in 1969 and named it Othniophyton elongatum , meaning "alien plant." At the time, they thought the fossil belonged to an extinct plant that was likely related to ginseng.

However, recent analysis has changed that hypothesis. Fossil expert Steven Manchester, curator of paleobotany at the Florida Museum of Natural History (USA), happened to see an unidentified plant specimen while visiting the paleobotany collection at the University of California at Berkeley.

The fossils are in a well-preserved collection and come from the same area where the first Othniophyton elongatum specimens were found.

The Manchester team of experts analyzed the fossils and concluded that they all belonged to the same type of tree.

During further investigation, they were unable to trace the origin of the specimens back to a database of more than 400 living and extinct families of flowering plants.

Both specimens were excavated in eastern Utah, near the abandoned town of Rainbow, also known as a "ghost" town.

About 47 million years ago, this place was a thriving lake ecosystem near active volcanoes.

Lake sediments and volcanic ash slowed the decomposition of fish, reptiles, birds and plants. Scientists have found many well-preserved fossils here, including two "alien" specimens.