In the Early Permian Huaibei Flora two fossil plant assemblages are recognized: a Callipteridium koraiense-Cathaysiopteris whitei-Cordaites schenkii assemblage and a Caulopteris spp.-Lobatannularia ensifolia-Gigantonoclea spp. assemblage. These assemblages are part of a small floral subprovince, the Xu-Huai-Yu region, that can be recognized and separated from the North Subprovince of the Cathaysian Floral Province on the basis of tectonic, climatic, and floristic features. The Xu-Huai-Yu region was an isolated depression surrounded by mountains and fault belts. It is a triangular area situated in northern Jiangsu, Anhui, and southern Henan Provinces of China. Because of its isolation and the climatic conditions in this region, a specific flora developed during the Permian evolving its own unique elements.