The geographical distribution of cycad plants in the geological periods in China

In this paper, the authors described in details the important discoveries and the geographical distributions of the reproductive organ fossils of the cycad plants which found recently in the geological periods of China. According to the demonstration of fossil materials, the distribution center of cycads in the Palaeozoic Era was located in the north part of China, and it developed gradually to the south part of China during the Mesozoic Era. It illustrated that the climate in the north China was better than the south China in Palaeozoic Era. It has proved also that the first cycad plant was growing in Carboniferous period of Palaeozoic Era. All of these are significant for the study of origins and evolution of the Gymnosper.