Recently discovered fossils of pollen grains discovered in drilling cores that came out of Switzerland put the evolution of angiosperms at about 100 million years earlier than previously thought. They have been dated to 240 million years old, at the beginning of the Early Triassic period.
The plants descended from conifers, ginkos, ferns, and cycads which were incredibly abundant around the time they emerged.
These flowering plants may have emerged much earlier than previously believed, but they still do not show up with any consistency until around 140 million years ago in the Early Cretaceous period. Around this time, fossilized pollen grain in the fossil record began to appear uninterrupted to present day.
Previously, molecular studies were used to estimate the age of the pollen, but the earliest samples were sparse and often of poor quality, making it incredibly difficult for scientists to agree on an exact timeframe. The newly discovered pollen grains were in remarkably good condition, making it much easier to image and subsequently date the samples. Peter Hochuli and Susanne Feist-Burkhardt from Paleontological Institute and Museum, University of Zürich feel that their work is so solid, they are confident that even some of the more skeptical scientists will agree that the evolutionary timeline of flowering plants has been pushed back to the Early Triassic, if not earlier.
Nearly ten years ago, the same researchers found closely related, though distinctly different, pollen grains from a plant that lived in the Middle Triassic. The current samples were found only 3000 kilometers (1860 miles) away.
There is no way to tell what these earliest flowers may have looked like. Though Switzerland is currently lush and green, it was much more arid during the period that these flowers existed.
The structure of the pollen suggests that insects likely helped pollinate the early plants, though these new samples could not have been aided by bees, as they wouldn’t be around for 100 million more years. Instead, it’s most likely that beetle species had pollination duties.