Primeval Palms

While hunting outside the Utah town of Redmond, Homer Behunin, 49, an amateur geologist, took a shot at a large male deer. The wounded buck ran off. As Behunin followed in hot pursuit, he stumbled onto a far more important prize: the fossilized remains of a primeval palm tree that may be the oldest flowering plant ever found.

At first glance, the 4-ft.-long, buff-colored fossilized log that Behunin discovered seemed not at all remarkable. It lay in a countryside of desert valleys in central Utah that 150 million years ago was a lush tropical shore along an inland sea, inhabited by huge flesh-eating dinosaurs. The area has thus yielded a rich supply of plant and animal fossils. Examining a specimen of the fossil under a microscope, Paleobotanist William D. Tidwell of Brigham Young University recognized the unmistakable cellular structure of the palm.

Principal Role. For Tidwell, that identification was startling. He knew that the fossil bed had been laid down during an age when earlier plants such as ferns and pinelike trees still dominated the earth's flora--some 50 million years before flowering plants are believed to have appeared. But palms are flowering plants, or angiosperms (from the Greek angeion, meaning container, and sperma, seed), and play the principal role in what Charles Darwin called "the great abominable mystery of biology." Angiosperms, which embrace everything from tropical palms and northern oak trees to Kentucky bluegrass and backyard rose bushes, had come to dominate the plant kingdom by the end of the Age of Reptiles, 75 million years ago. Indeed, angiosperms provided the essential food supply (grains, fruits) for the advent and survival of mammals, including man. But, Tidwell argues, no truly authenticated fossils of angiosperms more than 100 million years old have ever been found. How could angiosperms have risen to dominance in the relatively short period, on the evolutionary clock, of only 25 million years? If he could prove that his palm fossils were indeed 150 million years old, Tidwell realized, he could help solve the mystery.

Investigating the site themselves, Tidwell and his colleagues found two more fossilized palm logs. Near by, in the same geological formation, an oil company discovered ancient palm pollen. Other scientists, highly skeptical of the purported age of these finds, contended that they could easily have been washed down into the older sediment from higher and younger geological formations.

Original Position. While the scientists argued, Behunin discovered another important clue. This time he spotted what he thought were petrified twigs. Tidwell quickly identified them as roots of ancient palms. Furthermore, he noted that the roots were embedded in the sandstone in what was undoubtedly their original growth position. "This clinched it for us," Tidwell recalls. "There could now be no doubt that palm trees were growing in these sediments when they were being laid down and that the flowering plants had already established a foothold 150 million years ago."

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