Fossilized Tree Fern (IMAGE) University of California - Davis Caption This is a cross section of a fossilized Psaronius tree fern. Credit Jonathan Wilson/Haverford College Usage Restrictions Provide credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.