Abstract: Saururaceae is a small relict family distributed disjunctly between Eastern Asia and North America. At the present time it only contains 4 genera and 6 species. According to the com-prehensive analysis of the data from cytology, palynology, floral organogenesis and vasculature, embryology, comparative morphology and anatomy, the phylogenetic relationship among the genera of Saururaceae are inferred. The primitive genus Saururus with 2 species is considered much more primitive than the other three genera because it has preserved the probably most prim-itive characters from their ancester. Another Asian genus Gymnotheca with 2 species presents transitional group in the family.

Key words: Saururaceae

摘要： 根据细胞学、孢粉学、花器官发生和发育、花部维管结构、胚胎学、比较形态及解剖学等方面的证据，对三白草科4属6种的系统演化关系进行了详细论证。并联系古地理、古气候和古植物的有关史料对三白草科分布区的起源作了据理推论。三白草科大约起源于早白垩纪古北大陆东南部。它的原始类型可能与现代三白草属的形态大体相似，为一种多年生具根状茎的草本，花小、无被、具苞片。白垩纪末期三白草的原始类群已完成它在古北大陆的迁移和扩散，参与了南劳亚统一植物区系的组成。早第三纪以后在东亚和北美分别形成了两个分化中心。由于三白草科为喜温湿的亚热带类群，因而第四纪冰川之后，它在欧洲和西亚的成员灭绝，从而形成了东亚-北美间断分布的格局。东亚现存四分之三的属并代表着科内从原始到进化的各个阶段，是三白草科多样化中心和可能的起源地。

关键词: 三白草科, 系统演化, 地理分布