Permian palynofloras from Yongchang and Sunan of Gansu Province and their phytoprovincial characteristics

摘要

The Early Permian(Shansi + Lower Shihhotse Formations)palynofloras of Long- shoushan are dominated by Cathaysian_Euramerican common forms, mainly composed of pteri- dophytic and pteridospermous spores. But up to the Lower Shihotse Formation, gymnosperms greatly developed, and they possibly already dominated the vegetation in the Upper Shihotse formation; while in the late Late Permian, they indicate a strong colour of Subangara area.