Species Spotlight: Mountain Mahogany
Posted By The Friends of the Florissant Fossil Beds, Inc. on August 21, 2007
Mountain mahogany (Cercocarpus) is a small genus of deciduous shrubs or small trees, currently placed in the rose family (not closely related to true mahoganies, in the Meliaceae family). In addition to growing throughout the Rocky Mountain region today, mountain mahogany is a relatively common Tertiary (65 to 1.8 million years ago, the time between the extinction of the dinosaurs and the first Ice Age) fossil found in the Florissant and Antero Formations, as well as at Creede, Webber Lake in the Sierra Nevada of California, the Desert Peak Formation of Nevada, Oligocene sediments in Mexico, and many other localities.
Mountain mahogany seeds are more common than leaves in the Florissant Formation (34.07 million years old), although the numerous hairs of the modern seeds (above) are not evident–seeds are generally preserved as a small oval seed with a long curling tail. In certain localities in the nearby Antero Formation (~33.76 million years old), mountain mahogany leaves are the most abundant fossil. At left you can see the well-preserved part and counterpart of a mountain mahogany leaf from the Antero.
We haven’t found any mountain mahogany seeds like the ones from Florissant in the Antero yet, only leaves. Further study will show whether the Antero mountain mahogany more closely resembles the species from Florissant or the species from the Oligocene Creede flora, which grew in a much colder climate than that of ancient Lake Florissant.
-Melissa Barton
Photo Credits: Melissa Barton
The Friends of the Florissant Fossil Beds, Inc. is a nonprofit 501(c)(3) Friends of the Park group supporting 
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