Dicotyledonous Woods of the Cretaceous and Tertiary

白垩纪晚期和第三纪早期是开花植物历史上的关键时期。关于这一时期进化变化的信息来自于对叶子、花粉以及最近对花、果实和种子的研究。尽管开花植物的化石、石化木在美国的沉积物中随处可见，但对其解剖结构的系统研究却很少。北卡罗来纳州立大学的伊丽莎白·惠勒博士将研究几组白垩纪和第三纪树木的解剖学和分类关系，以扩大我们对特定植物群历史的了解。在研究期间所检查的森林结构特征的数据和来自文献的数据将编入一个计算机数据库。木结构随时间的变化将被跟踪，并与其他植物部位的变化进行比较。这个项目的成功在很大程度上取决于能否进入一个数据库，其中有大量现存物种的木材解剖资料。这种数据库已在北卡罗莱纳州立大学建立，并将加以扩大。这种扩展将有助于化石木材与现存植物的比较，并将有利于任何需要识别活植物和化石植物木材样本的人。

The Late Cretaceous and Early Tertiary periods are critical times in the history of the flowering plants. Information about evolutionary changes during this period has come from the study of leaves, pollen, and most recently, flowers, fruits, and seeds. Although fossil, petrified woods of flowering plants occur throughout deposits in the United States, there have been few systematic studies of their anatomy. Dr. Elisabeth Wheeler of North Carolina State University will study the anatomy and taxonomic relationships of several collections of Cretaceous and Tertiary woods, to extend our understanding of the history of particular plant groups. Data on the structural characteristics of the woods examined during the study and data from the literature will be organized into a computer database. Changes in wood structure through time will be tracked, and compared with changes in other plant parts. The success of this project is dependent to a large degree on access to a database with information on the wood anatomy of a large number of living species. Such a database has been established at North Carolina State and will be expanded. This expansion will facilitate the comparison of fossil woods to extant plants, and will be of benefit to anyone needing to identify wood samples of both living and fossil plants.