金粟兰科的起源,演化及其分布

本文利用形态解剖，孢粉学及化石资料，讨论了金粟兰科的系统；并对其起源，演化和现代分布格局形成等问题做了合理推测，主要结果如下：（１）Ｓａｒｃａｎｄｒａ和Ｃｈｌｏｒａｎｔｈｕｓ的亲缘关系最接近，而Ａｓｃａｒｉｎａ和Ｈｅｄｙｏｓｍｕｍ的系统位置最靠近。Ｓａｒｃａｎｄｒａ是金粟兰科中最原始的属，而Ｈｅｄｙｏｓｍｕｍ则是最进化的属。（２）金粟兰科可能于白垩纪最早期起源于木质部无导管的，具简单两性虫媒花的祖

ORIGIN, SYSTEMATICS AND DISTRIBUTION OF CHLORANTHACEAE

The origin systematics, fossil history and modern distribution of Chloranthaceae are discussed based on leaf architecture, wood anatomy, morphology and floral anatomy, palynology, fossil records and modern distribution pattern. Sarcandra and Chloranthus, both with bisexual and entomophilous flowers, have the closest phylogenetic relationship. Ascarina is most closely related to Hedyosmum both being unisexual and anemophilous. Sarcandra would be the most primitive genus in extant four genera of Chloranthaceae, on the contrast, Hedyosmum is the most advanced one. All proofs indicate that Chloranthaceae originate from the vesselless xylem and bisexual and entomophilous flower ancestor from which two groups derived. One is Sarcandra and Chloranthus and another Ascarina and Hedyosmum.The earliest fossil record of Chloranthaceae is from the Barremian of the Lower Cretaceous. Four extant genera of Chloranthaceae had occurred in the Aptin. This could indicate that Chloranthaceae originate before the Barremian. Extant Chloranthaceae mainly distributes in the regions of Caribbean, Venezuela and Surinam, Eastern Asian, Indo-chinese and Malesian. The regions richest in number of species of Chloranthaceae are Caribbean and Venezuela and Surinam including one genusand 40 species. Indo-chinese and Malesian regions however are most abundant in genera and the number of species only next to Caribbean and Venezuela and Surinam including four genera and sixteen species. In addition, there are the richest primitive species in these regions. Sarcandra, most primitive genus, distributes in these regions only. The Indo-chinese and Malesian regions, therefore are considered as the main distribution center and the center of the origin of Chloranthaceae. Caribbean and Venezuela and Surinam are Secondary distribution center. As the one of the oldest angiosperms, Chloranthaceae occurred in at least very early beginning of the Cretaceous. At that time, Laurasia was still a complete continent and Gonduana just started to break. Plants of Chloranthaceae disperse easily to other continent from their original place. With the plate movement, they were moved to different continent. Then they developed or reduced on different continent with the changes of the Paleoclimate and paleogeography and formed the present distribution pattern.