1. 2Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, P.R. China;
2. 5Institute of Geosciences, University of Tübingen, Sigwartstrasse10, D‐72076 Tübingen, Germany
3. 3Paléobotanique et FRE 2158 Centre National de la Recherche Scientifique (CNRS), Université Claude‐Bernard Lyon 1, Bâtiment Darwin‐A, 7 rue Dubois, F‐69622 Villeurbanne Cedex, France;
4. 4Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611‐7800 USA;