ONLINE IMAGE COLLECTION

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Image Title: x.s. of a Cycadeoidea stem
Image Credit: Patricia E. Ryberg, University of Kansas
Intended End User: Teacher, Student
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About the Image

Cycadeoidea (Bennettitales) is an extinct genus of seed plants that thrived in the Cretaceous (100 million years ago). This specimen was collected from the Black Hills of South Dakota. At the bottom of the picture is secondary xylem (wood) represented by the dark colored cells. At the top of the image is secondary phloem. Phloem is rarely preserved in the fossil record and the excellent preservation seen here is vital to studies on vascular tissue in fossil plants. (specimen from Yale University Peabody Museum of Natural History)


National Science Foundation  Development Supported by the National Science Foundation