The long isolation in the different phytogeographical units( i.e. the northeastern Gondwana unit and south China subunit during the Early Devonian) and different environment may result in the evolution and diversify of numerous endemics.

• 不同古植物地理区的长期隔离（也就是，早泥盆世的东北冈瓦纳古植物地理区和华南亚区）和独特的环境可能是造成众多地方性分子演化分异的原因。