Flowering Plants (Angiosperms)
Some of the trees and plants that lived in Denali in the Late Cretaceous had flowers. These are called angiosperms. They produce a wide variety of leaf types. Researchers have found at least 23 different leaf fossils in Denali, and many of them appear very similar to leaves we see around the park now.
Conifers, plants that have needles rather than leaves, are called gymnosperms. Conifer cones (like pine cones) and needles are common fossils in the Cantwell Formation. Spruce and pine trees seen today are modern forms of conifer trees.
Pteridophytes are plants that reproduce using spores rather than seeds and are the oldest type of plants on Earth. The first pteridophytes lived over 400 million years ago!
Horsetails (also known as equisetum) are another type of pteridophyte that existed 70 million years ago, and still exist in the park. Today these plants grow close to the ground, but in the age of dinosaurs horsetails could grow up to 100 feet tall. Most of the fossilized horsetails in Denali are under three feet. Horestails fossilize well because they contain a lot of silica, a mineral that makes the plant harder and more durable than most other plants.
Did You Know?
The vast landscapes of interior Alaska are changing. Large glaciers are receding, permafrost is melting and woody plants are spreading. Comparison of "then-and-now" photographs and data from major vegetation monitoring should allow detection, understanding and potential management of these changes.