Systematic Affinities, Age and Biogeographic Relationships of Fossil Floras from the Eocene Clarno Formation of Oregon

俄勒冈州始新世克拉诺组包含各种化石水果、种子、木材和树叶的组合。虽然在始新世植物地理学的讨论中经常被引用，但只有一小部分克拉诺植物区系被描述过。由于它包含了保存在各种沉积环境中的几种植物结构，可以用放射性计量学方法测定其年代，因此克拉诺组合在北半球始新世植物群对比中具有潜在的重要作用。对克拉诺植物群的综合处理，包括生殖结构和叶子，将促进欧洲早第三纪植物群与亚洲和北美植物群之间的洲际对比，欧洲的早第三纪植物群主要来自果实和种子，而亚洲和北美的植物群主要来自树叶。由此产生的数据集将更好地了解北半球始新世期间洲内和洲际植物区系的相对一致性，并深入了解植物地理迁移的时间和方向。

The Eocene Clarno Formation of Oregon contains a diverse assemblage of fossil fruits, seeds, woods and leaves. Although frequently cited in discussions of Eocene phytogeography, only a small percentage of the Clarno flora has been described. Because it contains several kinds of plant structures preserved in a variety of depositional settings that can be dated radiometrically, the Clarno assemblage is potentially important as a link in correlating Eocene floras across the Northern Hemisphere. A comprehensive treatment of the Clarno flora including reproductive structures and leaves will facilitate intercontinental correlations between the early Tertiary floras of Europe, known mostly from fruit and seed deposits, and those of Asia and North America, best known from leaves. The resulting data set will provide a better understanding of relative intra- and intercontinental floristic uniformity in the Northern Hemisphere during the Eocene and insight into the timing and directions of phytogeographic migrations.