Tree fern (IMAGE) University of Leeds Caption Tree ferns (Cyathea sp. and Dicksonia sp.) Older than the dinosaurs, tree ferns existed on earth long before the flowering or cone-bearing plants evolved. In some dense wet forest communities, the stems of tree ferns form entire tiny ecosystems, with epiphytic plants such as bryophytes, small fern species, lichens and even the seedlings of other plant species growing on their dense root trunks. Understanding ancient lineages of plants like these helps us better to understand the responses of our changing world to increased temperatures and climate change. Credit Annika Geijer-Simpson Usage Restrictions Must use credit License Original 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.