A new discovery of flowering plant fossils suggests they appeared about 100 million years earlier than previously believed, putting them in the Early Triassic period or further.

According to a press release, University of Zurich scientists analyzed an uninterrupted sequence of fossilized pollen. Pollen grains are the oldest known fossils of flowering plants, which have evolved from extinct plants related to conifers, ginkgos, cycads, and seed ferns.

Peter Hochuli and Susanne Feist-Burkhardt, both of the University of Zurich's Paleontology Institute and Museum, conducted the study, published Monday in the journal Frontiers. They analyzed two drilling cores from Weiach and Leuggern, northern Switzerland, and found pollen grains that appeared to be from the earliest known pollen fossils.

Hochuli said the discovery is important because fossils this extremely old were not previously available for flowering plants.

"That is why the present finding of flower-like pollen from the Triassic is significant," he said.

Previous studies had attempted to estimate the age of flowering plants and put them about 140 million years ago, in the Early Crustaceous period. But the current study suggests flowering plants first appeared at least 245 million years ago, putting them in the Early Triassic period.

One of those previous studies Hochuli and Feist-Burkhardt are trying to prove wrong, belongs to them. In 2004, Hochuli and Feist-Burkhardt studied samples from Barents Sea, just 3,000 km north of where they found the evidence for their current work.

The new discovery also puts the flowering plants ahead of the evolution of bees, meaning other insects, most likely beetles, pollinated the plants. In the Middle Triassic period, the Barents Sea and Switzerland were in the subtropics. Switzerland, however, was much drier than the Barents Sea region, meaning the flowering plants likely occurred at a broad ecological range.

Said Hoculi, "We believe that even highly cautious scientists will now be convinced that flowering plants evolved long before the Cretaceous."

(The author of this article corrected a mistakenly ommitted word in the first sentence, the numerical figure is "100 million," not "100".)