The Cathaysian and Euramerican floral provinces were both located in the equatorial regions in tropical climates, and some plants from the two areas had morphological similarities under similar climatic condition during the Carboniferous and Permian.

• 在石炭纪和二叠纪 ,华夏植物区和欧美植物区皆位于具热带气候的赤道区 ,在类似的气候条件下 ,这两个地区的一些植物具有形态上的相似性。